Unable to access the Administrative interface for applications installed from APS Catalog logged as customer:
PLESK_ERROR: Server Error
Cannot read properties of null (reading 'length')
The same application Administrative interface is accessible when logged as server Administrator.
#PPPM-13842 "Customers can now access the administrative interface of applications installed via APS Catalog."
- Plesk Obsidian 18.0.50 31 January 2023
If update is not possible for some reason you may try the following
Until the bug is fixed, navigate to the administrative interface URL manually and enter the credentials. e.g. for Joomla use "https://example.com/administrator"