notifications are not sent – cannot find any pattern

Hi,

I have searched through the FAQ, documentation and this forum but none of the solutions work (the solution is mainly “update version” which I always do).
I have a new post notification set up. It creates the email notifications but they remain in the queue unless I manually make them “send now” within a few hours after the notification is created. If a few hours pass (e.g. next day) and I haven’t manually sent them, they are in the status of “sent” but are not actually sent. Nobody receives the emails.
If I sent a manual email/campaign to my contact list, it seems like more people receive it.

Even when emails are sent, not all my subscribers receive them. I know for a fact that one person never receives them (they also checked their spam folder for me because with my own email address which is part of the list, the mails frequently land in spam)

I cannot find a pattern when the error occurs. I always update to the newest version within 2-3 days.

My last post notification did not sent emails although last week’s post did sent emails. I did not change any settings!

This plugin is very unreliable and I simply cannot get it to work. By now, I am quite frustrated. Any help appreciated.

The page I need help with: [log in to see the link]