I have a cPanel&WHM version 76.0.21 . I have restarted cPanel at 8:48, but I have received alarm i.e. many messages from cPanel Monitoring that services are failed after hour, but they are up.
I do not know why messages appeared when services are up?
This can happen on a reboot some times. As long as the number of restart attempts only says one and you are not getting them over and over again you are fine.
I agree with @GOT unless you're getting them every few minutes and there was only one restart attempt it sounds like the check for these servers happened at the time of reboot.
I also wanted to point out that we do have an improvement case open to look into this behavior where the notifications are sent on reboot. CPANEL-21627
I'll update here when there's any change in the case as well.