I have a weird problem with the link in the confirmation email.
When it’s clicked the first time it results in the following error 500:
AH01071: Got error ‘PHP message: PHP Fatal error: Call to a member function IsHTML() on null in /var/www/vhosts/domain.de/httpdocs/wordpress/wp-content/plugins/newsletter/plugin.php on line 726\n’, referer: http://domain.de/?na=c&nk=6-f843f1a153
However, when the same link is clicked a second time, it works and shows the “alternative custom welcome page” which I defined.
At the same time the “Welcome email” is not being sent. But disabling the welcome email does not solve the problem…
It’s weird, because line 726 in the plugin.php has something to do with sending a message, it seems ($this->mailer->IsHTML(false);) ?
Any help would be much appreciated…!
Thank you very much,