#5.5.0 smtp;554

[Michael]

I have a client who receives a variation of the following error when sending
to certain domains. Any ideas on how to resolve this?


There was a SMTP communication problem with the recipient's email server.
Please contact your system administrator.

<domain.name #5.5.0 smtp;554 <unknown[#.#.#.#]>: Client host
rejected: Reverse DNS lookup was unsuccessful>

[Lanwench [MVP - Exchange]]

Post by Michael
I have a client who receives a variation of the following error when
sending to certain domains. Any ideas on how to resolve this?
There was a SMTP communication problem with the recipient's email
server. Please contact your system administrator.
<domain.name #5.5.0 smtp;554 <unknown[#.#.#.#]>: Client
host rejected: Reverse DNS lookup was unsuccessful>

Check to see whether the client's public IP address has a reverse lookup in
DNS...

ping -a xxx.xxx.xxx.xxx

If there isn't one, ask the ISP to create one. they may even set it up to
match the FQDN used in the client's MX record, such as mail.domain.com . But
usually, the mere presence of a PTR is enough.

Also check out their domain name at www.dnsreport.com