Iphone 14 Pro Max says Incorrect WiFi Password (iOS 16.6)

My iPhone kept saying "incorrect password" when connecting to the WiFi, even though the password was obviously correct. I tried rebooting the phone, resetting network settings, but nothing worked. Then, for some reason it did connect finally. I thought all was well, but then it disconnected again later in the day while it was asleep in my pocket. When I woke it up it tried to connect to WiFi automatically like it always does, and now it's giving me the "incorrect password" again, even though it was already connected and I haven't changed anything!

How do I fix this?