Not working subtitles

So, I have this movie with Polish subtitles downloaded with Qnapi as txt file.
Txt won't work with BubbleUPNP, so I usually convert it into srt by:
`for i in ./*.txt ; do ffmpeg -sub_charenc cp1250 -i "$i" "$( echo "$i"|sed 's/\.txt//g' ).srt" && rm "$i" ; done`
I read somewhere that subtitles for castlink should be in VTT command, so I did:
`ffmpeg -i Movie.srt Movie.vtt`
After loading all info into chromecast.link movie starts but with no subtitles.
Can You help me?

Resulting vtt (part):
```WEBVTT

00:22.000 --> 00:25.900
Jurandinho

00:46.000 --> 00:48.520
Oto jedna
z "nieprawdziwych" historii,

01:24.000 --> 01:25.900
Faceci w Czerni

02:03.000 --> 02:05.000
znanych jako Faceci w Czerni.

02:44.000 --> 02:46.000
FACECI W CZERNI II

03:36.000 --> 03:38.000
Lipiec 2002

03:45.000 --> 03:47.000
Harvey!

03:51.000 --> 03:52.900
Harvey.
Do nogi!

03:55.000 --> 03:57.000
Harvey.
Harvey!

05:12.000 --> 05:14.000
SEKRET WIKTORII

06:07.000 --> 06:09.000
Co jest?

07:08.000 --> 07:09.900
Jasne.

07:10.000 --> 07:12.000
Jeff, staruszku.

07:13.000 --> 07:15.200
- Co tu robisz?
- Do ciebie mowa.

07:24.000 --> 07:26.000
Czego tu szukasz, glisto?

07:27.000 --> 07:27.900
T...

07:28.000 --> 07:29.900
Jeff....
```

By the way: awesome thing. Thanks for that.