[Errno 14] PYCURL ERROR 22

Sometimes, you can get this error:

[Errno 14] PYCURL ERROR 22 - "The requested URL returned error: 404 Not Found"
Trying other mirror.
...
[Errno 14] PYCURL ERROR 9 - "Server denied you to change to the given directory"
Trying other mirror.
Error: Cannot retrieve repository metadata (repomd.xml) for repository: sl-addons. Please verify its path and try again

But, don't  worry, server was turned off temporalily.