Unable to access Plesk GUI with the error:
Array and string offset access syntax with curly braces is no longer supported (lessc.inc.php:717)
Plesk was recently upgraded to 18.0.50 version.
The Auto-update feature is disabled from Extensions>Updates.
The version of the Skins and Color Schemes extension is outdated.
Log into the server via RDP.
Execute the command below to update the Skins and Color Schemes extension:
C:> plesk bin extension --install heavy-metal-skin