I am using odoo 15 version, accidentally I have archived the access rights and then the admin user is not able to edit another users. I have tried un archiving but there is no difference.
One more thing that I noted is there is no setting or other admin related menus appearing.
If I login as super user(admin username) I am able to create user but not able to make that user as admin, the administration section is not visible.
I know this is open question, sorry for that, the installation was done by other person, so not able to more details, please let me know how to reset the admin rights.
check table ir_model_access. column active=True. Try changing required record active field value to True