T-Online blacklisted SES IP addresses

Question

Hello,

we have a problem with T-Online.  
It seems that T-online blocks out AWS SES servers.  
Following bounces appear everytime my app sends a mail to T-online mailboxes with SES:  
  
```
smtp; 554 IP=23.251.226.12 - A problem occurred. (Ask your postmaster for help or to contact tosa@rx.t-online.de to clarify.) Status: 5.3.0
```

There were similar threads in the forum:  
https://forums.aws.amazon.com/thread.jspa?messageID=695663&#695663;  
https://forums.aws.amazon.com/thread.jspa?messageID=703368&#703368;  
  
Could you please urgently help to resolve this?  
Thank you!  
Lutz

Answer

Its happening again. We contacted tosa@rx.t-online.de  and also the form on https://postmaster.t-online.de/kontakt.php but they rejected our request as AWS needs to get in touch with them.

Answer

Hi!
We have the same problem since approximately begining of August 2022. T-Online seems to block SES IP adresses. I contacted T-Online at tosa@rx.t-online.de to clarify but they insist that Amazon contacts them to clarify.

If there is anyone here from Amazon, could you please help to resolve the issue? Thanks!

Best regards,
Frank

Answer

Unfortunately this keeps happening again and again with T-Online, but usually it only lasts a day or two - but this time ALL our emails to T-Online are getting reject for almost an entire week already and no solution in sight. This is affecting our business ...

@AWS any update on this issue?

Answer

Same here. Stopped working a few days ago...

Whats up @AWS?

T-Online blacklisted SES IP addresses

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