Hi @문영 임 · Thank you for reaching out.
The CName record that you have created in your DNS must point to the public/external FQDN configured in the app proxy settings. Once the Application Proxy service receives a request at the external url, it translates the url to internal url and forwards it to the server with app proxy connector installed. The connector server then forwards the request to the internal server which is hosting the web application. If you are getting 404, you need to check the logs on connector server if it is receiving the request or if there are any error while processing the request(s).
- Open Event Viewer and look for Application Proxy connector events in Applications and Services Logs > Microsoft > AadApplicationProxy > Connector > Admin.
- If needed, more detailed logs are available by turning on the Application Proxy connector session logs.
- Go get connector errors, you can use below command:
Get-EventLog application –source "Microsoft AAD Application Proxy Connector" –EntryType "Error" –Newest 1
Read more: https://learn.microsoft.com/en-us/azure/active-directory/app-proxy/application-proxy-troubleshoot
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