Recently (after 12th September 2020) the lightning component / LWC functionalities are no more working for some profiles. So this is due to the recent release enforced on preview instances in Winter 21.
Release details:
An authenticated user can access an @AuraEnabled Apex method only when the user’s profile allows access to the Apex class.
Solution:
So you need to give access of related Apex class to concerned profiles.
This can be done in two ways;
- Go to profile -> Enabled Apex class access -> Edit -> Add the Classes and Save
- Go to the class -> Click on Security -> Select Profiles and add to enabled profiles -> Save
Related release note: https://releasenotes.docs.salesforce.com/en-us/winter21/release-notes/rn_lc_restrict_apex_authenticated_users.htm
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