Cannot play media filesTelevisions, Blu-ray players, or other UPnP-compatible playback devices or software cannot play individual photos, videos, or music pieces from the FRITZ!Box media server. When you try to play them, the device may display the error message "not supported file format" or "unknown file format".1 Changing the file extension of MKV video files for use with Samsung devicesSamsung...
> https://en.avm.de/service/knowledge-base/dok/FRITZ-Box-7690/680_Cannot-play-media-files/
MyFRITZ! login failedYou cannot log in to myfritz.net or the MyFRITZ! home page of your FRITZ!Box. After you enter your account information, the error message "Login failed" or "Invalid username or password" is displayed. Since your FRITZ!Box only transmits the IP address where it can be reached in the internet to the MyFRITZ! service but not any personal data, two different login processes take...
> https://en.avm.de/service/knowledge-base/dok/FRITZ-Box-7690/1597_MyFRITZ-login-failed/