system update fail daily

Hello,

I fail daily scheduled system safe update.
Error Description: [Errno 256] No more mirrors to try.
Update from Plesk GUI also fail.

Plesk auto-update is off.

I run the below command.
(1) rm -fr /var/cache/yum/*
(2) yum clean all
Then when I check for update, all applications are reported as up to date.
However, the next day's automatic update fails.
The application to be updated is the same as the previous day.
It seems that the manual update was not possible either.

The...

system update fail daily