I am using another plugin that adds newly registered users to a CM list. In combination with the GF add on there's a fatal error when submitting a GF form (note: this GF form does not use CM functionality).
Fatal error: Cannot redeclare CS_REST_SERIALISATION_get_available() (previously declared in /path-to/wp-content/plugins/ajax-cm-forms-premium/createsend-php/class/serialisation.php:7) in /path-to/wp-content/plugins/gravityformscampaignmonitor/api/class/serialisation.php on line 13
I contacted the author of the CM-Forms Premium plugin, and got the following answer:
My plugin checks whether the Campaign Monitor API code has been included, and only includes it if it's not already defined. It looks like the Gravity Forms plugin always includes it without checking. It seems WordPress is loading my plugin first, and then the Gravity Forms plugin.
Would there be any solution for this? I would really like to use both plugins.
Thanks in advance.