I woke up and tried to send an email and keep getting this message: The server response was: Service unavailable; Client host [73.106.75.21] blocked using sbl-xbl.spamhaus.org; https://www.spamhaus.org/query/ip/73.106.75.21
My IT guy said his email is on the same server and it is fine that this is a problem on Mac's end. I NEED to work today and don't know what to troubleshoot. PLEASE HELP
MacBook Pro
If your IT guy had been bothered to do a quick 30-seconds worth of checking he would have found this:
https://mxtoolbox.com/SuperTool.aspx?action=blacklist%3a73.106.75.21&run=toolpage
How he can say: ". . . a problem on Mac's end . . ." is beyond me? Having been the "IT guy" for IT solutions providers mainly dealing with email servers and of course email I have to ask why he's fobbed you off with such a feeble excuse. Go back again and ask him/her what steps did he/she take in deducing its a problem with your Mac?
The IP address that's been blacklisted by Spamhaus is owned by Comcast, one of America's largest ISPs.
That IP address has no rDNS pointer which is probably why its been black-listed. All MX records should resolve their DNS on both forward and reverse pointers to be fully trusted otherwise they run the real risk of being deemed an open relay or a mail server involved in sending out lots of spam. Hence the black-listing.
I'll see if I can do a bit more digging for you (something your IT guy should be doing for his fellow work colleagues) so what is the domain you're trying to send the email too? I just need the part after the @ symbol.
Mail (Mac) stopped sending emails today.
