Not sure why this would make a difference but AFAIK the registration and forgot password emails are sent at runtime. Notifications and whatever else are queued. That is why I asked if the registration emails were failing.EA117 wrote: ↑Sun Jan 27, 2019 12:52 pmIt's not clear, for me anyway, that we're looking at a blocked or blacklisted scenario currently. Since success or failure seems to depend upon the content of the message being sent. ("Forgot password" fails, others do not fail.) If the reputation of the originating mail server was the issue, I would be expecting all messages to fail.
Spam filters score an email, a reverse DNS issue for example would cause a score that would always cause a rejection on most of them. Minor issues may not cause an email to be rejected however if you have enough minor issues they may add up to a score to reject it. There may be minor difference between the forgot password emails and the notifications causing the rejection of the forgot password email but there is other underlying problems.
For example if you do not have SPF record that can cause higher score, fix that problem and the minor issues become irrelevant. Using the mail tester it can tell you what these problems may be.
To me the biggest "crime" in all of this is that you weren't immediately receiving back a rejection notice, by email, confirming that the send attempt was being dropped.
When this occurs it's usually reverse DNS issue that most email servers drop into a blackhole because it will almost always be a spammer. This is not something that should occur and if that is the issue you need to contact your host to fix it. It's not something you can fix yourself even on higher end server plans.