I upgraded my service tier on only our App Service app (not the other resources). A day after doing this, the app will no longer start up - giving the following:
HTTP Error 500.30 - ASP.NET Core app failed to start
If I connect to the App Service portal and use Kudu to start it via a debug cmd prompt, I see
Microsoft.Data.SqlClient.SqlException (0x80131904): A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: TCP Provider, error: 0 - No such host is known.)
System.ComponentModel.Win32Exception (11001): No such host is known.
Storage queue startup also fails with my queue hostname. In kudu I also tried
C:\home\site\wwwroot>nameresolver mydatabase.database.windows.net
Server: Default
Can't find mydatabase.database.windows.net: Non-existent domain
(not my actual server name...) but same thing for google.com or any other hostname
also:
C:\home\site\wwwroot>ping 142.251.32.142
Unable to contact IP driver. General failure.
but this seems to be expected?
I am not using any fancy VPNs, private networks, groups or whatnot - this is as plain vanilla as I could make it. This worked for months before the upgrade. It works when run locally. My firewall for the database allows all azure services and my work/remote IP. I tried connection strings in the app service configuration only as well as only in appsettings.json. The connection string works in VS 2019, 2022, and sql management studio as well as the query tool within Azure portal itself. I've restarted the App service many times. OpenDNS cache check shows multiple different IPs for my database server but is this expected for regions? Why is the DNS apparently broken? How can I get this back to a functional state?
