[dnceng-bot] Branch `aspire/main` can't be mirrored to Azdo fast forward branch

Branch [main](https://github.com/microsoft/aspire/commits/main/) in `microsoft/aspire` repo can't be mirrored from GitHub to Azure DevOps [main](https://dev.azure.com/dnceng/internal/_git/microsoft-aspire?version=GBmain&_a=history) via fast forward.
There was unexpected error during the mirroring process.

unexpected http status code: 503

Problem need to be **resolved to unblock the code flow**.

You can troubleshoot the issue by:
- checking the logs of the mirroring process in the [mirroring pipeline](https://dev.azure.com/dnceng/internal/_build?definitionId=1387).
- by trying to mirror the branch manually
- you can disable the mirroring of the branch in the [configuration file](https://dev.azure.com/dnceng/internal/_git/dotnet-mirroring?path=/dnceng-subscriptions.jsonc).
- you can ask @dotnet/dnceng for help or read the [documentation](https://dev.azure.com/dnceng/internal/_git/dotnet-mirroring?path=/README.md).

Please close this issue once the problem is resolved.