Same problem - same exact error, however my cert is not self-signed, its a legit cert from LetsEncrypt. Worked in all previous iOS versions for decades, still works on MacOS. But iOS18..... no more email.

Count me in. I've been googling all over trying to find some detailed information and authoritative documentation for this feature and I find NOTHING. Other than the 15 year old half a paragraph from the iOS 4 documentation linked to above. One would think there must be documentation somewhere, but where? The fact you have to use the image resolution, I have not seen that documented absolutely anywhere, just comments in stackexchange posts. This is crazy! And i REALLY want to add a launch screen to my webapp. This is a real bummer :/

I have a mac mini home server that has been crashing every approx. 15 days for over a year now. Its a 2012 mini running Catalina. It does what I call a half crash where many services fail, though I can still make http requests sometimes and I can still SSH in. But no way to see what's going on or sniff out the problem. Then through random chance, I was connected to the mini through screen sharing and turns out it was hours or less before it was going to crash. Memory pressure was super high, yellow with blips into the red. And it was from CloudKeychainProxy! It was clearly leaking and it's memory use was going up and up and up. Slowly, but steadily. SO after about 15 days, my 16 GB system would run out and not fully lock up but functionally lock up. My first clue in i don't even know how long. It's been going on so long, I actually have been logging these crashes on a calendar to see if I could infer any clues that way! I don't know what you mean by "reset [the] keychain" but what ended up working for me was logging out of iCloud entirely. I don't really NEED iCloud services on this home server, so for now I just logged out. After a few minutes, all that leaked memory suddenly started deflating and use and pressure all went back down to normal. Not sure if I'm going to try to log back in and dig around and see if I can solve the problem, OR if I'm just going to leave it as-is without iCloud. But if nothing else, let me chime in to say I TOO HAVE TROUBLE WITH CloudKeychainProxy LEAKING MEMORY SLOWLY AND SURELY UNTIL THE SYSTEM IS UNUSABLE!