Subtitles does not load and show automatically

[stroke]

SMplayer version: 17.10.2 (version 8735)(64-bit)
Movie file name: X.mp4
Subtitles file name: X.txt
I have set: "The same as movie title" and "Choose first available subtitles" checked.
Any ideas?

[rvm]

Does it work if you change the extension to srt?

[stroke]

Yes. I changed subtitles file extension to srt without any conversion and it worked.
Is there any way to do this fot txt subtitles files?

[rvm]

I don't know if it's possible to fix this, because the subtitles are actually auto loaded by mplayer/mpv.