Website in Plesk server unavailable after switching to PHP 7.x: Call to undefined function mysql_connect()

Symptoms

• Website in Plesk server is unavailable with the following message:

  CONFIG_TEXT: Call to undefined function mysql_connect()

• In the Domains > example.com > Applications > Manage Available Applications > <Application name> the error below occurs:

  PLESK_WARN: Warning: The app was not configured: Non-zero exit status returned by script. Output stream: 'PHP Fatal error: Uncaught Error: Call to undefined function mysql_connect() in /usr/local/psa/var/apspackages/apscatalogJB3Muy.zip33615037-b2fc-e2/cache/scripts/db-util.php:66

• In Plesk for Windows the following occurred in Domains > example.com > Logs:

  PLESK_ERROR: 500 PHP Fatal error:Uncaught Error:Call to undefined function mysql_connect()...

Cause

According to official PHP documentation mysql_connect() function has been completely removed in PHP 7.x. Thus it is not possible to enable function not supported by the vendor.

Resolution

1. Log into Plesk;
2. Switch to the 5.x PHP version in Domains > example.com > PHP Settings: