Hello,
I am being blocked by Yahoo with the error message: 451.4.4.0 Primary IP address responded with "421 4.7.1 [TS03] All message from x.x.x.x will be permanently deferred; Retrying will NOT succeed. See http://postmaster blah blah blah.
I found that this is a problem with the DKIM and I used https://github.com/Pro/dkim-exchange open source to try and remedy this but I was unsuccessful. I don't think I am doing anything wrong as I followed the instructions to the letter.
These are the results of the auth-results@verifier.port25.com email.
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Summary of Results
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SPF check: pass
DomainKeys check: neutral
DKIM check: neutral
Sender-ID check: pass
SpamAssassin check: ham
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Don't know what other info to give...
Please help...