I see that it works for new users, for users that were created with the previous version of wplms it does not work, it is seen that it is a permission problem with the users.
Ok then please goto wp-admin -> lms -> settings -> api -> connected clinets -> clear all clinets
and then try taking quiz .
this should work . Secondly make sure that in wp-admin -> lms -> settings -> api -> Enable api and all settings are enabled as mentioned in this tip :
https://wplms.io/support/knowledge-base/quizzes-on-react/
thanks for your confirmation
closing this one