If you hosts using cPanel haven’t figured it out just yet, there’s a fun issue where customers routinely cannot send mail unless they repeatedly try until it works. The bug was introduced with the fix to the 21 exim vulnerabilities on May 04, 2021.
Today, July 06, 2021, this bug is still live in cPanel servers and users experience it to varying degrees seemingly at random. The bug is simply this:
“condition check lookup defer”
According to cPanel this has been noted to occur when a user hits email quota, and can sometimes be fixed by restarting Dovecot. None of this is true. It cannot be solved without a software patch, not even briefly. Any correlation with a fix is merely correlation with the randomness of the behavior to begin with.
At this time, cPanel is holding back a fix for version 98 with plans to backport it at that time. However, cPanel 98 is not even on their testing tier at this time. It’s release date is unknown, possibly far into the future. That’s two months so far that many, if not all, cPanel servers are broken. Due to the intermittent and random nature of it, customer complaints may not be plentiful, but the bug is there and has been confirmed on all of our cPanel servers at MXroute at this time.
In a year where cPanel has continually raised prices in an effort to extort their client base (“Would be a shame if you had to migrate…”) and shake them down for every penny, they’ve released a major bug in the usability of their platform which threatens to go unchecked for at least a quarter of a year.
This needs to be spread louder. Anyone considering the purchase of a cPanel license needs to be aware. Take your money elsewhere. I don’t know what they’re using it for, but it isn’t development.