The german Telekom mailservers - don't accept mails send from SimpleLogin

[Pamalosebi]

Sadly, Mails send through SimpleLogin do not arrive in mailboxes hosted by the german Telekom (T-Online).
They are very restrictive but should accept mails send by SimpleLogin.

They have a "rule-set" which has to be applied on a Mailserver before they accept mails of it.
-> https://postmaster.t-online.de

The postmasters offer a special mailaddress if a service is (wrongly) blacklisted: postmaster@rx.t-online.de

Given reasons for being on a blacklist:

• Posting of "Backscatter"
• use of "Sender Address Verification"
• missing spam filter for outgoing e-mails
• missing or insufficient Abuse Management

[nguyenkims]

@Pamalosebi thanks for the information. Though the document at https://postmaster.t-online.de/index.en.html#t3.5 seems complete, a quick glance shows its strange decision regarding industry standards such as SPF, DKIM or popular technique as grey listing:

ISP email service sometimes have issues with properly handling emails and when that happens too often, we have no choice rather than redirecting users to a "proper" email service like ProtonMail, Tutanota, etc or even Gmail, Outlook.

[Pamalosebi]

redirecting users to a "proper" email service

yes, I am with you. They have some "specialties".
In this case, it is used by a rather large number of people. One get one of these mailboxes with the network providers contracts.
Therefore, many just stick with it.

[Konfekt]

@nguyenkims : For T-Online to be able to unblock Simplelogin, please send postmaster@t-online.de the following information as follows:

• The IP of the Simplelogin e-mail server
• The times when it sent e-mails to T-Online (for example, today twice at 16:03)
• The rejection messages it received by t-online.de

[nguyenkims]

We have sent to this address some info, hope we'll have their responses quickly.

[SamuelBlickle]

Any news about this? I'm experiencing the same issue.

[nguyenkims]

Unfortunately we haven't heard back from t-online yet, we'll try to do a follow up with them.