User does not have sufficient privileges to perform requested action

We need a bit more context.

Hello [mention:0e1c3eb422644ea29b8410d42c320506:e9ed411860ed4f2ba0265705b8793d05] 

When are you seeing this Error Message.
How are the securities defined? Are we talking about object securities or Data securities as well?

Could it be that you were added to the right group during your active session and hence it will take effect after you refresh or re-login? Did you try that?

Something that happens in higher environments that doesn't happen in lower environments could also be a user being set as an administrator (in a dev environment) vs a basic user (in a higher environment). Could also be that they are perhaps a member of the application administrator group in a lower environnent whereas they are not in that group in a higher environment.

we are using getgroupsformembersuser function.

Scenario : Let's assume we have 2 groups

group A- User X , User Y

group B - User E, User F

getgroupsformembersuse(username: user X) is working as excepted 
but not for getgroupsformembersuse(username: user E) and is throwing error - " The user Incorrect privileges to get groups for user. [User Context: user E] does not have sufficient privileges to perform the requested action ".

privacy settings for group A and B has same.
and visibillity of both groups also set to public.