Ideas
I'm having the same problem on a Samsung laptop. I can't save lots to my gallery due to a server error. This just started on March 21; at first, I got the error, but the lots still saved. Now, I get the error and the lots won't save, I'm trying to save existing lots that I've modified. The plumbobs spin and spin, then, the error appears. I use mods and cc. I've updated or removed all of the broken mods and cc that were reported since the EA updates or that caused LEs in the last week. My DirectX version is DX 12. Thank you!
Edited to add: Suddenly, about 15 minutes after I tried to save it, multiple saves for the lot I used in the sample below have appeared in my gallery. I tried saving another lot, too. Maybe that will show up later.