why doesn't apple photos & videos load on any device

Hi

I have 2Tb iCloud an iPhone 12pro max, MacBook & iPad. All are up today software and I've restarted all to try and resolve problem.

I can't access videos on the apple app or most photos. Either there is a cloud with an exclamation or a circle with an exclamation or an error message unable to load photo An error occurred while loading a higher quality version of this photo (or video if I'm trying to watch a video)

I have tried with wifi, hard wired and 4G to ascertain if it is an internet problem. I have a large amount of family photos and videos that I would be devastated if I lost them. As most are irretrevable.

In addition I tried accessing through browser and it says Due to account maintenance this account is locked. Try again in an hour.

This has been the same for the last 48hours