did you clear your cookies after the password change? decentmeme knows from a cookie that "it's you" using it and since you gave it posting permission via @decentmemes.app already it does not need any of your keys anymore. If this cookie is still there from before the password change, you can still post on decentmemes without entering your key again. Try on a different browser or in a private tab, then it should only accept the new keys.