MKA is an audio-only Matroska container developed by Matroska which can contain any supported audio codecs, but no video. You can use some modern media players like VLC, KMPlayer to play it. But it's still not compatible with most devices. So an easy solution is to convert MKA to MP3 since MP3 is our common-used audio format and have a high compatibility with most smartphones, tablets, TV sets, editing software as well as other portable devices. To convert the audio file from MKA to MP3, a good mka to mp3 converter is needed. You can use online service or mka converter software to convert MKA file to MP3, MKA to FLAC, MKA to AC3, MKA to WAV, MKA to AAC, etc and keep the original audio quality.

I see you put a link directing to video converter factory. Actually, I think Pavtube Video Converter Ultimate will better to re-encode MKA to MP3.