I am unable to send an email to an anonymized craigslist relay address. I've tried several times. Copy/pasted the address so I know it is correct. This particular ad is going to expire this afternoon so I needed to send it soon.

I get the following error:
Unable to send message;Reason:554 5.1.8 Email Outgoing Blocked

I *can* send email to other recipients, and to myself!

I am a very light email user but am going to want to reply to more craigslist ads and job ads in the near future. The craigslist email relay itself has been flakey enough from past experience so I don't need more problems on my end...

Please advise! Thanks!