Edit the file vendor/magento/module-authorization/Model/Acl/AclRetriever.php at line# 85 and replace the below code

   if (!$role) {
     throw new AuthorizationException(
         __('We can\'t find the role for the user you wanted.')
     );
 }
 $allowedResources = $this->getAllowedResourcesByRole($role->getId());

With this one

if (!$role) {
            $allowedResources = array();
        }

Once success, please revert back the file.