PHP error: Unable to load dynamic library ‘/usr/lib64/php/modules/apc.so’ undefined symbol: zend_new_interned_string in Unknown on line 0

Symptoms

PHP fails with a similar warning:

# php -v
PHP Warning: PHP Startup: Unable to load dynamic library ‘/usr/lib64/php/modules/apc.so’ – /usr/lib64/php/modules/apc.so: undefined symbol: zend_new_interned_string in Unknown on line 0
PHP 5.3.3 (cli) (built: Dec 11 2013 03:29:57) Copyright (c) 1997-2010 The PHP Group Zend Engine v2.3.0, Copyright (c) 1998-2010 Zend Technologies

Cause

PHP module got corrupted after the PHP re-installationupgrade.

Resolution

1. Connect to the server via SSH;
2. Restart the plesk-php-fpm service:

   # service plesk-php53-fpm restart

   Note: plesk-php53-fpm can be replaced with the required PHP version (e.g., plesk-php56-fpm, plesk-php71-fpm and etc.)

3. If it does not help, re-install the PHP module mentioned in the error:

   # pecl uninstall apc
   # pecl install apc