I have selected a mp3 ringtone, but when I am called, only a slow “ding…ding” sound is played. I checked both in Settings --> Sound and in Phone --> Settings - the correct ringtone is set.
The mp3 worked fine on my previous Android 8.0 device. I saw that mp3 is in the list of supported file formats. Also, the file can be played by VLC on the device itself, so I can rule out file corruption.
Any ideas on how I can get my own ringtone to play?