SOLVED 550 Invalid RCPT (thank you for using SPF)

[WorkinOnIt]

Hello team

I hope you are doing great! I am wondering if you can assist with the following. I know there are many topics on this issue - though mine seems to be unique as far as I can tell !!

I keep getting mail bouncing back to one single email address and I cannot seem to identify where/what the issue is - whether this is a setting on my server - or if it is the remote server. There are no other issues on my server.

Email has been working fine to the recipient - until yesterday and now I get a bounce back (below) from my server - regardless of what I send them. There have been no changes on my server (other than a recent upgrade to version 62 build 15).

I am hoping you might be able to tell me if this is an issue with their domain or with the receiving server - or if I should add something to my cpanel config?

This message was created automatically by mail delivery software.

A message that you sent could not be delivered to one or more of its
recipients. This is a permanent error. The following address(es) failed:

info @clientdomain.com
host mailx.theirhostdomain.com [123.45.678.910] example ip
SMTP error from remote mail server after RCPT
TO:<[email protected]>:
550 Invalid RCPT (thank you for using SPF)

I have not seen this exact message before - especially the 550 Invalid RCPT "thank you for using SPF" - which I have googled but found no matches!!

I've checked my sending server IP in blacklists and all is fine. However, I did notice that their domain does not have an SPF record. Could that be the issue - though I assumed SPF was more for "sending" rather than receiving (Sender Policy Framework). Could the absence of an SPF cause recipient issues?

Strangely - if they send me an email - I seem to be able to reply without issue. Also I tried send them an email from my personal Gmail account - that bounced too.

I have contacted their domain host and waiting for their reply - perhaps my sending server is blocked by them?

Thanks in advance.

 

[cPanelMichael]

Hello,

Could you search one of the affected messages in /var/log/exim_mainlog and let us know the output? EX:

exigrep [email protected] /var/log/exim_mainlog

Thank you.

 

[WorkinOnIt]

Hello - problem solved - I finally discovered the mail host had inadvertently suspended the account without any notification to the customer! Needless to say, problem solved by moving them to a new host!

 

[cPanelMichael]

Hello,

I'm happy to see you were able to determine the cause of the problem. Thank you for updating us with the outcome.