I have upgraded Prestashop from 8.1.1 to 9.0.1. Everything worked fine but I am unable to login into the admin backend.
Below is the log when I submit the login form:
request.CRITICAL: Uncaught PHP Exception Doctrine\ORM\NonUniqueResultException: "More than one result was found for query although one row or none was expected." at AbstractQuery.php line 973
The error was as follows:
The solution was to delete old, additional records for my user from the table ps_employee.
I hope this helps someone else!
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