Playing MKV files on phone

[Amirax]

Has anyone met the same problem as me...I can't open a converted file on my phone, but usually, it worked pretty fine. Were there any updates lately?

[Woodstock]

Lots of unknowns here.

Does your phone play MKV files? Apple phones won't, unless you use a third-party app. Android running 6 and later can play MKVs with the built-in viewer, but there are problems with audio sync... so a third-party app is usually needed.

Are you processing the MKV files to MP4?