Errors upon activation:
Warning: Undefined array key “license_key” in /wp-content/plugins/fluentcampaign-pro/app/Services/PluginManager/LicenseManager.php on line 423
Warning: Cannot modify header information – headers already sent by (output started at /plugins/fluentcampaign-pro/app/Services/PluginManager/LicenseManager.php:423) in /wp-admin/includes/misc.php on line 1416