Hi Guys, I have the infamous “421 4.7.1 [TS03] All messages from xx will be permanently deferred; Retrying will NOT succeed. See http://postmaster.yahoo.com/421-ts03.html” error from Yahoo. My mail server is set up with reverse DNS, SFP, DKIM and has passed every check I can think of, yet Yahoo block it. I can not find my IP on any blacklist (or anywhere else on google apart from dnstools etc). I have opened a case with Yahoo 5 times so far and their automated machines close the case each time with “we’ve made appropriate changes to the IP address(es) in our database” but it makes no difference. Anyone got any ideas on what to do next? The only solution I can think of is to get all my friends to leave Yahoo and to get proper email addresses! The other way might be to change the IP address of my droplet - how hard is that and is it likely to work? Any other ideas?
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