Docker build pull access denied, repository does not exist or may require
You have stages called base, build, and debug. Then in the final stage you have:
COPY --from=publish/app /app .When docker can't find the stage with that name, publish/app, it tries to find that image, which doesn't exist. I'm guessing you want to copy from the build stage, e.g.
COPY --from=build /app .
Are you logged in? Try with docker login and then execute docker build once again
As I can see here aspnet in docker hub the repository that you intent to use has been renamed. Use the following instead
from mcr.microsoft.com/dotnet/aspnet:3.1-buster-slimRepositories have been renamed and a similar issue can be found here similar issue