Connection problems with local mail clients

If difficulties occur when setting up the mailbox account using a client (e.g., Thunderbird, Outlook, ...), this can have various reasons. The two most common problems are Telekom routers and so-called security programs.

Telekom routers

Some Telekom routers come with a pre-enabled function called "Secure Mail Servers." Since the SMTP server from mailbox is not entered there, all outgoing connections via the standard SMTP ports are automatically blocked. To resolve this problem, there are two options: either you manually add mailbox to the list of "secure mail servers," or you deactivate this function.

Security suites / antivirus programs

Various security suites have an email scanning feature enabled in their settings that blocks ports. At the moment, the only solution is to deactivate this feature. We have already contacted the manufacturers to have mailbox added to the whitelist.