Enhanced Mail System Status Code

[nweiler]

Hi

I'm running a Qmail on Redhat 7.3.

One of my client is not able to send any email to me and always get the Enhanced Mail System Status Code : 5.1.2

I'm sure he got the email address correct. After doing some research, error 5.1.2 means permanent failure due to invalid email address.

Is this error due to the sender's email server being not able to verify the existance of the receipient (my client's email address)? Anything to do with DNS?

Thanks for any lead or help.

 

[thedaver]

does his email address contain any "." period characters or anything other than alhpa-numerics in the username portion left of the "@"???

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