For these, I'm not even seeing the request arrive.

The closest connection from you on that day seems to be 12:23 UTC (but no requests to save a puzzle).

I do see a successful save at 11:17 UTC, but that's it

No idea yet what the cause could be

Sorry, I didint post this earlier.

In March, this happened a lot to me. I was on vacation, and we discovered early on, our internet connection was BAD. After we were able to contact the company and got some improvement in internet speed, I didnt have this problem.

Another data point for Patrick. I was trying to save today’s medium sudoku around midday today and it froze on me. I eventually quit out of the puzzle and when I went back in, my changes had nor been saved.

For the record, I’m currently in Portugal and the Wi-Fi signal here is not as good as at home.