I've got a repeating problem with my users not being able to get logged in. So I've had this weird problem, and it's been "solved" twice, but it's back...and I think it might be something to with the cache and nonces.
The first time, Katya helped me, and she thought it might be my security plugin. I disabled Defender and Wordfence, and login worked....when I reenabled both, it still worked.
Then it happened again, and this time it got resolved when I deleted the (huge) wp debug log file.
Today it happened again, and by now I've done some reading and thought I'd see if it was cache related -- when I disabled wp-cache I was able to log in.
So how do we go about following up on this to figure out what's wrong under the hood?