TLS Configuration: www.neomailbox.com (178.209.46.154)
Network Error A network error occurred while we were trying to communicate with a server.
Error message: connectionClosed
Network access blocked
One or more tests in this section couldn't complete because network access was blocked.
This usually happens when there are rate limiting controls in place. SMTP servers are often very sensitive and refuse access at the slightest dislike of the client.
Error message: Server refused service: 421 Too many concurrent SMTP connections from this IP address; please try again later.
Just to give you an update: I added neomailbox.com to the slow list a couple of days ago, but that didn't solve the network errors. I think there may be another issue there.
I noticed two network errors here:
Network Error A network error occurred while we were trying to communicate with a server.
Under the HTTP section:
Maybe they rate limit.
Now they have two domains, there's also neomailbox.net mentioned in their guide.
Here we see: