Debian - Postfix - Unable to send e-mail @yahoo

Hi, I’m French, so first excuse me for my english.

My problem is that I can not send an e-mail to

Here is the message in log (mail.log) :

Sep 23 10:10:31 jeremydevos postfix/smtp[21221]: 93487411BA: to=<>,[]:25, delay=0.4, delays=0.01/0.04/0.13/0.22, dsn=4.7.1, status=deferred (host[] said: 421 4.7.1 [TS03] All messages from will be permanently deferred; Retrying will NOT succeed. See (in reply to MAIL FROM command)).

With MXTOOLBOX everything is OK :

SMTP Banner Check 	OK - resolves to
	SMTP Reverse DNS Mismatch 	OK - Reverse DNS matches SMTP Banner
	SMTP TLS 	OK - Supports TLS.
	SMTP Connection Time 	0.905 seconds - Good on Connection time
	SMTP Open Relay 	OK - Not an open relay.
	SMTP Transaction Time 	3.245 seconds - Good on Transaction Time

Thank you for your help

Submit an answer

This textbox defaults to using Markdown to format your answer.

You can type !ref in this text area to quickly search our full set of tutorials, documentation & marketplace offerings and insert the link!

Sign In or Sign Up to Answer

These answers are provided by our Community. If you find them useful, show some love by clicking the heart. If you run into issues leave a comment, or add your own answer to help others.

Want to learn more? Join the DigitalOcean Community!

Join our DigitalOcean community of over a million developers for free! Get help and share knowledge in Q&A, subscribe to topics of interest, and get courses and tools that will help you grow as a developer and scale your project or business.

That looks like yahoo has permanently blacklisted your ip. At some point in time a spam server was most likely using that ip.

About the only thing you can really do is get new ip. Unless someone has an easier method the only way I can think of doing this is by:

  1. Snapshot the server.
  2. Recreate server from snapshot.
  3. Update all the DNS entries A recrods MX, etc records and such point to new ip.
  4. Destroy original server

Good luck.