Can't find any online and idle self-hosted or hosted runner in the current repository

Build is failed due to the following error:

Can't find any online and idle self-hosted or hosted runner in the current repository, 
account/organization that matches the required labels: 'ubuntu-latest'

Found online and busy hosted runner(s) in the current repository's organization account that matches 
the required labels: 'ubuntu-latest'. Hit concurrency limits on the hosted runners. Waiting for one of 
them to get assigned for this job.



Waiting for a hosted runner in 'organization' to pick this job...

The build status: Delete dependabot.yml · hantsy/spring-r2dbc-sample@d98b632 · GitHub

Did you ever find a solution to this?

I encountered some wired issues of Github actions in the previous projects, most of time it may be caused by some Github system upgrade or some unknown issues for end users. And then it will disappear after a while.