Suddenly no emails sent anymore by subscribe2- but no system changes made

Dear all,

first I need to tell I’m not a programmer, just a girl from Germany owing a blog (feinkostpunks.de) and I’m trying to do most administrative things on my own, which worked out good until I discovered the following problem:

I have been using subscribe2 for a while and everything worked out fine. I have about 1.700 subscribers.

From end of April, suddenly no user received my emails anymore when I added a new article. I didn’t change any settings, not in wordpress, not in subscribe2, not in the domain hosting account. In addition to this problem, some other things happened at the same time:

– when I uploaded a new Blog entry, instead of the normal page I received a more or less unspecific error page. As I can’t see how to add screenshots, it says (translated from German): Dear visitor, unfortunately a problem occurred. The requested page has caused a script error. ” (there is some request to try again, use the correct url, just the normal stuff, nothing specific). This issue is automatically solved when I de-install the subscribe2 plugin, so it seems it’s causing the issue.

– The emails are not sent to the subscribers anymore, but the 2nd defined group (registered subscribers, only me) still received the emails. I have added someone for testing to this group for a while, it worked. But both of us didn’t receive the Blog entry title, it only says “TITLE” instead (which is the placeholder for the blog entry title, but this never happened before)

– trying to send a normal email via the system to all affected users to explain the issue ended up with the same error page. Sending a message to the “registered users” (2 people at that time) worked out fine, including subject and mail content.

This is what was already done to solve the issue, without success:

– de-install and install subscribe2

– tried from different computers with different systems and browsers to make sure it’s not one of THESE issues

– make sure the email address is correct so I’m sending emails from the blog, not from another address anymore (was an issue some time before, but already fixed by adding the correct email to the basic wordpress settings)

– Updated PHP and mySQL in the domain hosting service

– checked with the domain hosting company for any rules they have regarding email sending. They do have some, but they confirmed in several talks this does not apply for my problem. They disconnect for a second after 1.000 emails and re-connect immediately, so this shouldn’t be a problem. They told me if this was the issue, I’d have seen a related error message explaining the problem.

What they did was to check the error logs. This is what they sent me:
“For your request, there was no connection to the SMTP-Relay, we got this message: Sorry,_I_wasn’t_able_to_establish_an_SMTP_connection._(#4.4.1)/”

Unfortunately, this is where I totally reach my limits as I’m not a programmer. Might be the issue can be solved easily, but could you check and give some advice?

Thanks in advance,

Danja from Cologne (Feinkostpunks.de)

https://wordpress.org/plugins/subscribe2/