Contact your supplier - it’s normally a source issue.

Sometimes changing the resolution to 720p if you are using BUZZ or DREAMLINK works, or like Sylocule said, it's an issue with your providers decoding.

You could try changing your stream format, select a different player like VLC over the default one and/or change the decoder from whatever it is to software or hardware. You can probably do all these things in your app settings. Trial and error with the various combinations of settings.