For us, a few weeks ago Azure DevOps randomly stopped processing GitHub webhooks, so merge commits didn't trigger builds anymore (and we're not the only ones, see https://developercommunity.visualstudio.com/content/problem/...). A fix for this issue still isn't deployed.
Just a few days ago the service connection to Azure suddenly stopped working with "401 CouldNotFetchAccessTokenForAzureStatusCode" which appeared when deploying to Azure AppService. We had to recreate the service connection to get it working again.
Recently we also wanted to move our Android builds to Azure DevOps but in the end the documentation was so confusing that we just used Bitrise instead.
It does not work unless Github is open to the internet. For example, Github Enterprise behind a VPN will not be able to use Azure Devops. Crazy but true.
Just a few days ago the service connection to Azure suddenly stopped working with "401 CouldNotFetchAccessTokenForAzureStatusCode" which appeared when deploying to Azure AppService. We had to recreate the service connection to get it working again.
Recently we also wanted to move our Android builds to Azure DevOps but in the end the documentation was so confusing that we just used Bitrise instead.