As TLS v1.0 was been deprecated in June 2018 (see this blog post), and TLS 1.1 in April 2022, Kolab Now  removed those from our servers. Some users has been complaining that now they can not connect to kolabnow.com anymore. They get various different error messages about SSL and TLS problems.

The problem is, that the client software and/or operating systems is old, and are relying on the old TLS v1.0 or TLS v1.1:

Linux:

Make sure that your SSL implementation is supporting TLS 1.2 or later. For the most common SSL implementation, OpenSSL, this is version 1.0.1 or later. If a different implementation is installed, then please check with the relevant documentation.

OSX (Apple Mail):

Support for TLS 1.2 was added to OS X 10.11.4 (and later) by the replacement of OpenSSL with LibreSSL 2.1.8. If your version of OS X are older than that, please upgrade.

Windows:

Microsoft issued an article with a recommended update addressing the TLS 1.0 and TLS v1.1 issue. Please note, that the fix requires change to the Windows Registry. If you run an updated Windows machine you should however be Ok and not have any of these issues.