Spam filtering problem (resolved)
Due to what appears to be a DNS issue at a third party, a small number of messages that weren’t actually spam may have been incorrectly blocked by our mail filters over the last few hours.
We’ve made changes to our system to ignore these errors, making sure no other messages will be blocked.
The number of affected messages was small enough that this wasn’t an issue for most customers. However, if someone tells you they sent a message that was initially blocked with an error message about “red.uribl.com”, but which later went through without problems, this problem was the cause of that.
We sincerely apologize to anyone who had trouble.