Error validating user: <Username>

Error Message

After upgrading Portal for ArcGIS, attempts to log into the Portal for ArcGIS website using a non-administrator account fail, and return the following error message:

Error:   
Error validating user: <Username>

Cause

The Portal for ArcGIS version upgrade is incomplete as the post-upgrade steps were not performed. The post-upgrade steps are done to authorize the users and apps in Portal for ArcGIS.

Solution or Workaround

Log in to the Portal Administrator Directory with an administrator account, and perform the post-upgrade steps before logging in to the Portal for ArcGIS website using a non-administrator account. Refer to Steps 8 to 22 of ArcGIS Enterprise: Perform an upgrade of your portal deployment for more information regarding the post-upgrade steps required after upgrading Portal for ArcGIS.