You're viewing **Apigee Edge** documentation. [Go to the **Apigee X** documentation](http://cloud.google.com/apigee/docs/api-platform/reference/api-proxy-configuration-reference). info > [!NOTE] > **Note:** Was this troubleshooting playbook helpful? Please let us know by clicking [Send Feedback](). ## Symptom The client application gets an HTTP status code of `404` with the message `Not Found` and the error message `Unable to identify proxy for host: VIRTUAL_HOST and url: PATH` as a response to the API calls. This error means that Edge could not find the API proxy for the specified virtual host and path. ## Error message The client application gets the following response code: ``` HTTP/1.1 404 Not Found ``` In addition, you may observe an error message similar to the one shown below: ``` { "fault":{ "faultstring":"Unable to identify proxy for host: default and url: \/oauth2\/token", "detail":{ "errorcode":"messaging.adaptors.http.flow.ApplicationNotFound" } } } ``` ## Possible causes | Cause | Description | Troubleshooting instructions applicable for | |---|---|---| | [Virtual host with duplicate host alias](https://docs.apigee.com/api-platform/troubleshoot/runtime/404-multiple-virtual-hosts-same-host-alias#vh-dupl-host-alias) | Multiple virtual hosts have the same host alias and port number. | Edge Public and Private Cloud users | ## Common diagnosis steps > [!NOTE] > **Note:** This section applies to Private Cloud users only. NGINX and Message Processor logs will be helpful in troubleshooting the `404` error. Use the following steps to check the logs: 1. View the NGINX logs using the following command: ``` /opt/apigee/var/log/edge-router/nginx/ORG~ENV.PORT#_access_log ``` 2. Check for the following fields in the log entries: | Field | Value | |---|---| | `Upstream_status, status` | `404` | | `X-Apigee-fault-code` | `messaging.adaptors.http.flow.ApplicationNotFound` | Make a note of the message ID from the logs. 3. Check the Message Processor logs (`/opt/apigee/var/log/edge-message-processor/logs/system.log)` to see if you have `messaging.adaptors.http.flow.ApplicationNotFound` for the specific API or if you have the unique message ID from step 2 for the API request. **Sample error message from Message Processor log** ``` NIOThread@1 ERROR ADAPTORS.HTTP.FLOW - AbstractRequestListener.onException() : Request:POST, uri:/weather, message Id:null, exception:com.apigee.rest.framework.ResourceNotFoundException{ code = messaging.adaptors.http.flow.ApplicationNotFound, message = Unable to identify proxy for host: vh1 and url: /weather, associated contexts = []}, context:Context@342ea86b input=ClientInputChannel(SSLClientChannel[Accepted: Remote:10.123.123.123:8443 Local:10.135.33.68:62092]@1206954 useCount=1 bytesRead=0 bytesWritten=0 age=1ms lastIO=0ms isOpen=true) ``` 4. The log above shows the error code and error message is as follows: ``` code = messaging.adaptors.http.flow.ApplicationNotFound, message = Unable to identify proxy for host: vh1 and url: /weather ``` > [!NOTE] > **Note:** The `url` and `host` above may vary depending on the API proxy for which you are having the issue. ## Cause: Multiple virtual hosts with the same host alias and port number Apigee Edge Routers and Message Processors use both the host header, port number and URI paths to route traffic to the correct API proxy. Having ambiguous definitions such as multiple virtual hosts with the same host alias and port number is a documented [anti-pattern](https://docs.apigee.com/api-platform/antipatterns/multiple-vhosts) and can lead to unexpected behaviours. One of the common errors that you will observe is a `404` error with the message `Unable to identify proxy for host: VIRTUAL_HOST and url: PATH`. Typically if multiple virtual hosts with the same host alias exist, then you will observe intermittent `404` errors. This is because the specific API Proxy may be configured to accept the requests on only one of the virtual hosts. When the API requests are routed to the specific virtual host that is configured in the API Proxy, you will get a successful response. However, when the API requests are routed to the other virtual hosts to which the API Proxy is not configured to accept the requests, then the APIs will fail with these `404` errors. **Note:**The multiple virtual hosts having the same host alias and port number can be in the same environment of an organization or across different environments of an organization as long as they share the same routers. Follow the instructions given in [404 Unable to identify proxy for host: \ and url: \](https://docs.apigee.com/api-platform/troubleshoot/runtime/404-unable-identify-proxy-host) and troubleshoot this error. If none of the causes are leading to this error, then use the steps below to determine if virtual hosts with duplicate host aliases are causing the `404` errors. ### Diagnosis Use one of the following methods to determine if there are multiple virtual hosts having the same host alias/port # leading to `404` errors: - Edge UI - Management APIs #### Edge UI **Note:** These instructions are applicable for both Public and Private Cloud users. Use these instructions to determine if there are multiple virtual hosts having the same host alias/port # using the Edge UI. For example, if you observed the `404` error with the url `http://example.com:9001/proxy1`, then you need to find which virtual hosts have the host alias `example.com` and port `9001`. 1. In **Public Cloud** and **new Edge UI on Private Cloud** : 1. Select **Admin**. 2. Select **Virtual Hosts**. 3. For each **Environment** use the search filter to determine the **Virtual Hosts** that match the specific **Host Alias** with which the API requests were invoked. 4. If you find multiple **Virtual Hosts** using the same **Host Alias** go to [Resolution](https://docs.apigee.com/api-platform/troubleshoot/runtime/404-multiple-virtual-hosts-same-host-alias#resolution) to resolve this issue. **For example:** ![](https://docs.apigee.com/static/api-platform/images/ts-404-mult-virtual-hosts-public-cloud.png) 2. In **Classic UI on Private Cloud** : 1. Select **APIs**tab. 2. Select **Environment Configuration**. 3. Select **Virtual Hosts**. 4. For each **Environment** view the list of **Virtual Hosts** to see if any match the specific **Host Alias** with which the API requests were invoked. 5. If you find multiple **Virtual Hosts** matching the same **Host Alias** go to [Resolution](https://docs.apigee.com/api-platform/troubleshoot/runtime/404-multiple-virtual-hosts-same-host-alias#resolution) to resolve this issue. **For Example:** ![](https://docs.apigee.com/static/api-platform/images/ts-404-mult-virtual-hosts-private-cloud.png) #### Management APIs **Note:** These instructions are applicable for both Public and Private Cloud users. Use these instructions to determine if there are multiple virtual hosts having the same host alias/port # using the Management APIs. 1. Get the definition of each of the virtual hosts in each of the environments in your organizations to see which virtual hosts have the same host alias and port number: For example, if you observed the `404` error with the url `http://example.com:9001/proxy1`, then you need to find which virtual hosts have the host alias `example.com` and port `9001`. 1. Get the list of environments **Public Cloud user:** ``` curl -v -X GET https//api.enterprise.apigee.com/v1/organizations/ORGANIZATION_NAME/environments -u USERNAME ``` **Private Cloud user:** ``` curl -v -X GET http://MANAGEMENT_HOST:PORT#/v1/organizations/ORGANIZATION_NAME/environments -u USERNAME ``` Where: ORGANIZATION_NAME is the name of the organization **Example:** ``` curl http://127.0.0.1:8080/v1/organizations/myorg/environments -u USERNAME ``` ``` [ "prod", "test", "dev" ] ``` 2. Get the list of virtual hosts in an environment **Public Cloud user:** ``` curl -v -X GET https//api.enterprise.apigee.com/v1/organizations/ORGANIZATION_NAME/environments/ENVIRONMENT_NAME/virtualhosts -u USERNAME ``` **Private Cloud user:** ``` curl -v -X GET http://MANAGEMENT_HOST:PORT#/v1/organizations/ORGANIZATION_NAME/environments/ENVIRONMENT_NAME/virtualhosts -u USERNAME ``` Where: ORGANIZATION_NAME is the name of the organization ENVIRONMENT_NAME is the name of the environment **Example:** ``` curl http://127.0.0.1:8080/v1/organizations/myorg/environments/test/virtualhosts -u USERNAME ``` ``` [ "default" ] ``` 3. Get the definition of each of the virtual hosts in the environment. **Public Cloud user:** ``` curl -v -X GET https//api.enterprise.apigee.com/v1/organizations/ORGANIZATION_NAME/environments/ENVIRONMENT_NAME/virtualhosts/VIRTUAL_HOST_NAME -u USERNAME ``` **Private Cloud user:** ``` curl -v -X GET http://MANAGEMENT_HOST:PORT#/v1/organizations/ORGANIZATION_NAME/environments/ENVIRONMENT_NAME/virtualhosts/VIRTUAL_HOST_NAME -u USERNAME ``` Where: ORGANIZATION_NAME is the name of the organization ENVIRONMENT_NAME is the name of the environment VIRTUAL_HOST_NAME is the name of the virtual host **Example:** ``` curl http://127.0.0.1:8080/v1/organizations/myorg/environments/test/virtualhosts/default -u USERNAME ``` ``` { "hostAliases" : [ "example.com" ], "interfaces" : [ ], "listenOptions" : [ ], "name" : "default", "port" : "9001", "retryOptions" : [ ] } ``` 4. Repeat the above two steps for the other environments in your organization. In this example, repeat the steps for the `dev` environment: ``` curl http://127.0.0.1:8080/v1/organizations/myorg/environments/dev/virtualhosts -u USERNAME ``` ``` [ "default" ] ``` ``` curl http://127.0.0.1:8080/v1/organizations/myorg/environments/dev/virtualhosts/default -u USERNAME ``` ``` { "hostAliases" : [ "example.com" ], "interfaces" : [ ], "listenOptions" : [ ], "name" : "default", "port" : "9001", "retryOptions" : [ ] } ``` In this example you can see that the two virtual hosts `default` in two different environments, `test` and `dev`, both contain the same host alias `example.com` and port number `9001`. This is the cause for `404` errors. 5. If you find multiple **Virtual Hosts** matching the same **Host Alias** go to [Resolution](https://docs.apigee.com/api-platform/troubleshoot/runtime/404-multiple-virtual-hosts-same-host-alias#resolution) to resolve this issue. ### Resolution 1. Ensure that each virtual host only contains unique host alias and port combinations. 2. If you have identified multiple virtual hosts with the same host alias and port combinations then you must update these with a unique host alias. 3. You can update these using the Edge UI or the Management API, instructions can be found under [Modifying a virtual host.](https://docs.apigee.com/api-platform/fundamentals/configuring-virtual-hosts#modifyingavirtualhost) 4. Ensure that each host alias has a proper DNS entry. **Note:** If the duplicate host alias was found in a virtual host configured on *secure* port such as `443`, then you need to procure a certificate that matches the new host alias name or has the new host alias in SAN (Subject Alternative Name) in an existing certificate used in the keystore. 5. In the example discussed above if our configuration looked like this: ``` curl -X GET http://localhost:8080/v1/organizations/myorg/environments -u user ``` ``` [ "prod", "test", "dev" ] ``` ``` curl -X GET http://localhost:8080/v1/organizations/myorg/environments/test/virtualhosts/default -u user ``` ``` { "hostAliases" : [ "example.com" ], "interfaces" : [ ], "listenOptions" : [ ], "name" : "default", "port" : "9001", "retryOptions" : [ ] } ``` ``` curl -X GET http://localhost:8080/v1/organizations/myorg/environments/dev/virtualhosts/default -u user ``` ``` { "hostAliases" : [ "example.com" ], "interfaces" : [ ], "listenOptions" : [ ], "name" : "default", "port" : "9001", "retryOptions" : [ ] } ``` 1. You can update the incorrect virtual host such that they are not overlapping. 2. That is update the host alias as `example2.com`. 3. Ensure the new host alias has a similar DNS entry as the previous host alias. ``` curl -X GET http://localhost:8080/v1/organizations/myorg/environments/dev/virtualhosts/default -u user -H 'Content-Type: application/json' -d '{ "hostAliases" : [ "example2.com" ], "interfaces" : [ ], "listenOptions" : [ ], "name" : "default", "port" : "9001", "retryOptions" : [ ] }' -i ``` ``` HTTP/1.1 200 OK Date: Tue, 02 Feb 2021 20:54:29 GMT Content-Type: application/json X-Apigee.user: user X-Apigee.organization: myorg X-Apigee.environment: dev X-Apigee.backends: management-server Date: Tue, 02 Feb 2021 20:54:29 GMT Content-Length: 152 { "hostAliases" : [ "example2.com" ], "interfaces" : [ ], "listenOptions" : [ ], "name" : "default", "port" : "9001", "retryOptions" : [ ] } ``` 6. Make the API calls again to the proxy and verify that you are getting successful responses consistently: ``` curl http://example.com:9001/proxy1 ``` ``` { "slideshow": { "author": "Yours Truly", "date": "date of publication", "slides": [ { "title": "Wake up to WonderWidgets!", "type:": "all" }, { "items": [ "Why WonderWidgets are great", "Who buys WonderWidgets" ], "title": "Overview", "type": "all" } ], "title": "Sample Slide Show" } } ``` 7. If the problem still persists, go to [Must gather diagnostic information](https://docs.apigee.com/api-platform/troubleshoot/runtime/404-multiple-virtual-hosts-same-host-alias#must-gather). ## Must gather diagnostic information If the problem persists even after following the above instructions, gather the following diagnostic information, and then contact [Apigee Edge Support](https://docs.apigee.com/api-platform/troubleshoot/support): If you are a **Public Cloud user**, provide the following information: - Organization name - Environment name - API Proxy name - Complete `curl` command to reproduce the `404` error - If the `404` errors are not occurring currently, provide the time period with the timezone information when `404` errors occurred in the past. If you are a **Private Cloud user**, provide the following information: - Complete error message observed for the failing requests - Organization, Environment name and API Proxy name for which you are observing `404` errors - API Proxy bundle - NGINX access logs `/opt/apigee/var/log/edge-router/nginx/ORGANIZATION_NAME~ENVIRONMENT_NAME.PORT#_access_log` - Message Processor logs `/opt/apigee/var/log/edge-message-processor/logs/system.log` - The time period with the timezone information when the `404` errors occurred