Staff changes won't be saved

Hi, 

I have been experiencing this problem for the last two days. We have a Medical Service where patients can schedule their appointment via Bookings. I tried to make some changes on staff availability, and names, but it doesn't save the changes. I can add new staff, but won't allow me to change any availability on the new staff neither. I make the changes, I save, and when I re-open the staff edit page, no change has been applied. 
Any solution to this problem? I've tried to erase the cache, tried to access the bookings page from teams, outlook, chrome, edge and modzilla. Nothing works. 

Thank you!