@xvilo @stardot Your instance does only support TLS 1.2 and not 1.0 and 1.1. This causes problems with Tusky on old Android 4.x versions. We tried several workarounds in Tusky to no avail. Tusky will stop supporting Android 4 in 2018 as it only makes about 7% of our users so we will not investigate this any further, sry.
So if you get any reports like this please always ask for the used Android version, on 5+ everything should work.
There are 4 ways to get Tusky: On F-Droid, on Google Playstore, on Amazon Appstore or download the apk directly from the Github release page. All have exactly the same code and differ only in the signing key, which is specific to the store.
Good news: Tusky 1.4.1 is finally available on f-droid!