Host Restriction

I'll hazard a guess that your brother or his ISP use abusix to filter emails destined for his email address. And for some reason your domain name is either on a blacklist or has a malformed or missing SPF record.

Probably just telling you that if you want to know more about why your email has been rejected by their mail filters you can go to that URL.

You are very lucky to *get* a bounce message these days! Most stuff that fails SPF is dropped silently on the floor without warning. It catches out a lot of small businesses whose ISP's have sloppy mail configs.

I never get emails from people with misconfigured SPFs any more. My ISP simply drops them on the floor likewise with most hostile binary threats unless it really is a zero day exploit and not in their danger list.

MXTools is helpful for finding which org is blocking the domain name.

Cheers

It's all plain text here.

I contacted my ISP 'abuse' link and copied the details.

They've been blocked and cleared and blocked again . . .

Morons or bots at both ends of the trail.

RL

Tried it with and without attachments.

They don't care who or what it is, just dropping the whole Primus domain, it seems.

Both my brother's and my original ISPs were gobbled up decades ago. Mine used to be just down the street. His was publicly owned telecom . . . went to *ell.

RL

RL

I'm guessing you are using either a small ISP company, or you have your own domain name and your emails are going through third party hosting service. Other users of the same service are sending large amounts of spam, which is causing the IP address to be flagged by the "monitors". Some email servers use these monitoring services to block potential spam. When it happens, it's a PITA, as it is hard to get off the list without being put back on very shortly.

The real culprit is your provider, because they are not using sufficient means to detect and block such spam. Often they will impose a limit on the total number of outgoing emails. But this may, or may not be sufficient to get rid of the spammers.

Commercial RBL provider so far as I can see. the details seem to be buried under many layers of marketing crap.

They don't like your domain name and you'r brothers mailbox privider trusts their judgment. the info at the URL you got may explain why they don't like your domain name.

SFAIK legit.