403 is a not allowed, try to ask the provider about that error. It is rather strange since that panel has nothing that should trigger a block. Probably it is the apache mod security intercepting some words… for example, have you a list named “update”?
Stefano.
Just now noticed that I receiving the following message.
“The WP scheduler doesn’t seem to be running correctly for Newsletter.”
That is another problem, it means the internal WP scheduler is not triggered. You can setup an external trigger following the examples in our documentation.
https://www.thenewsletterplugin.com/documentation/delivery-and-spam/newsletter-delivery-engine/
