Hello there,
I‘ve got a problem: a big German ISP who is also offering a mail address to his customers (*@t-online.de) is rejecting mails from my MIAB server.
According to my MIAB backend, I’m not on Spamhaus’s list. T-Online must have their own list or so.
What can I do?
Kind regards,
Kortschnoi
Can you share the error message or bounced email info?
Also, if you’d share your Miab hostname, I can check that all settings are correct wrt DNS. PM is fine.
Hi alento,
Thank you for your reply.
I don’t know how to PM here. Seems like new users can’t?
The error is that your IP address is specifically blocked by t-online. It may be for one of a couple of reasons. Did you run a blacklist check tool such as https://mxtoolbox.com/blacklists.aspx ?
If your IP comes up blacklisted there, follow the instructions to request unblocking. Some blacklists do not remove IP’s from their blacklist, but most do upon request.
If you are not on one of those blacklists, then follow the instructions and email tosa@rx.t-online.de for assistance. When I have to email I do a couple of things. First I email from the postmaster account (using an identity in the email client) and second I am always sure to mention that I just received this IP address and intend to run a mail server - I am not responsible for the prior usage.
This usually works if the company is responsive.
Thank you very much for your help, alento! 
I mailed T-Online. Let‘s see what happens.
Good luck.
Mostly, it works.
For google, you can also register your domains at postmaster.google.com. Gmail also has sometimes this kind of strange things.
T-Online’s postmaster answered and told me I should contact my postmaster. 
In this case, you can contact your VPS provider support and ask them if they would contact t-online
Good luck with that though.
I didn’t give up and replied to T-Online. Unlisting takes place within 24 hours.
Did you get your IP successfully whitelisted? I’m having the same issue. Apparently, t-online.de puts entire IP blocks from hosting companies (like linode) and ISPs (like TWC) in their black lists by default.
I emailed the contact address and was given a few key bits of information. First, was that hosts that are de facto anonymous to third parties are not qualified for delisting. I’m trying to figure out what this means. Does this refer to making the domain registration information public?
The second thing was from their docs at https://postmaster.t-online.de/index.en.html, Chapter 4.1, which state, among other things, that I must “ensure the host’s domain leads to a website providing full contact details.” Has anyone setup a Webpage like this before?
@Kortschnoi: Have the same issue. I fulfilled all neccessary requiremends by t-online, as far as I understood, but didn’t succeed.
I forwarded a failed delivery report alongside a polite message to tosa@rx.t-online.de and got whitelisted within 24 hours. My VPS provider is Digital Ocean. No further action was required in my case.
I did the same about 3 years ago. No issues, resolved in a day. I’m also with DO
