Issue: Requester details are not populating in configurable portal
Cause: The logged in user may not have permissions on User Information List.
To auto populate Requester details, give read permissions for everyone on User Information List.
Go to Site Settings in root site –> People and groups (in Users and Permissions section) –> Click on List settings under Setings (refer below image)
It will take us to the User Information list, open "Permissions for this list" (under Permissions and Management)
Grant read permissions for "Everyone" on this list (refer below image).