troubleshooting Question

Exchagne rejecting email with error 550 5.7.1 Recipient not authorised. your IP has been found block listed

Avatar of Om Joshi
Om JoshiFlag for United Kingdom of Great Britain and Northern Ireland asked on
ExchangeSBS
7 Comments1 Solution3931 ViewsLast Modified:
I am stuck with this issue for long and trying to find a solution

many spam emails get through to existing mail boxes in exchange but some genuine work related emails senders complain about below mentioned error

"550 5.7.1 recipient not authorized, your IP has been found block listed"

when I check the SMTP receive log i see that recipient email address is known he/she is a existing user in the organization.

I am wonder the reason why exchange is throwing such error when its recipient and sender both are genuine and do not contain spam or meet the SPAM criteria.

awaiting prompt response on my query.

regards,
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