we had this problem a week ago my friends got it to we thought it`s a game bug but when one of us toun off all addons he could list his key we started to toun addons 1 by 1 to c witch one cousing this bug and it was leatrix we download old version and it work
the old virsion is 9.2.17

The player that has the key in their bag and is trying to list the dungeon in premade group finder - does that player have two-factor authentication on their account?

If the answer is no, install the latest release of LTM (currently 9.2.21) and that should resolve it.

If this doesn't help, install the latest release of LTM anyway and explain what happens when the player tries to list the key in premade group finder.