After logging in Plesk Panel I am getting the error:
This file is part of Plesk distribution. It cannot be run outside of Plesk environment.
But it is possible to get the list of subscriptions, customers and domains by direct link https://localhost:8443/left.php3
Plesk Mobile Extension 1.4(or older version) is installed and it is not compatible with Plesk 12.
Software issue, internal request ID is PPPM-1639
Install the latest Plesk 12 microupdate
"%plesk_bin%"\ai.exe --select-product-id panel --select-release-current --reinstall-patch --install-component base
Remove Plesk Mobile extension or update it by opening directly:
Go to 'Extensions' -> 'Extensions Catalog' -> Click 'Update'