I have a user who says that he cannot login or set his password.
He is getting the error message: “Couldn’t reset password because the token is expired”.
I’ve searched Google and the forum but cannot find a solution.
I’m not encouraged by the level of support here 
Can you reproduce this problem?
If not, you and your user need to figure out what is different on this specific system. It can help to test a different browser, perhaps TOR browser (to avoid any interaction with an extension or the ISP filtering/optimizing/securing stuff). Try a different user on the same machine, try the same user on a different machine, …
I Think this issue is linked to https://github.com/nextcloud/server/issues/6023
Not yet resolved but seems to be better in the futur version NC 14. I wait for it. Go to github and vote for it !