This is the message I receive if I have a URL in an email I personally send. Because LJ sends URL links to updated entries, I can only assume it causes the same type of error:
--
The mail system
<[deleted]@q.com>: host mx.quartz.synacor.com[205.169.121.11] said: 554 5.7.1
Message...
I have a Livejournal account that sends email update notices to a relative's q.com account. Lately, q.com email has been blocking any email with a URL in it and will not permit messages from Livejournal.
Livejournal has been whitelisted on the q.com account already. What other spam filter...