Conflict between MailPoet and Purity theme

My mailpoet plug-in in Wordpress shows a 3rd party conflict with the theme Purity. I can’t send test mails for the newsletter and only 20 of 270 newsletters have been send. When I open another theme, the written conflict is gone. Who can tell me what to do? All Plug-ins have been updated (Wordpress as well). Thanks!

If the plugin is part of the theme then the author may be able to help.

If it’s a third party integration that was not part of the demo then you may need to hire help and can try