Send to MPV player using context menu not opening video

[GoodGuyNick]

If try to open second video here(Steins;Gate 0 Episode 23 Ending Song | Gate of Steiner by Eri Sasaki), mpv will not open. mpv will start trying to open link but then just quits. The same goes if you try to open this video from recommended sections. It will only work if opening video and pressing button from toolbar.
I don't have this issue with Open With.

[belaviyo]

What is your browser and what is your OS?
So if you use the toolbar button it works just fine but the context menu causing the external player to be closed? Do you have --keep-open=yes in the command-line options? Also try to open the player first and then try to send the links to the player using this extension.

[GoodGuyNick]

Ubuntu 18.04, Firefox 62.0.3.

So if you use the toolbar button it works just fine but the context menu causing the external player to be closed?

yes

Do you have --keep-open=yes in the command-line options?

no

My config:

--hwdec=vaapi
--ytdl-format=bestvideo[height<=?1080]+bestaudio/best
--player-operation-mode=pseudo-gui
--ontop
--geometry=--0--0
--autofit=25%
--save-position-on-quit
--sub-pos=0
--alang=eng,en,english, en-GB, en-US
--slang=eng,en,english, en-GB, en-US
--sub-scale=0.6
--idle=no

While I was testing your addon I disabled and enabled it multiple times and now I don't have it in context menu. Uninstalling and installing native-messaging-hosts helped. I had not encountered this issue with Open With.

Also try to open the player first and then try to send the links to the player using this extension.

It opens second instance of mpv with "No file"

[belaviyo]

In the options page of the extension add --keep-open=yes to the command-line and see if it helps.

While I was testing your addon I disabled and enabled it multiple times

This is an error with Firefox's start-up event. Just close the browser and reopen it for the items to appear.

[GoodGuyNick]

In the options page of the extension add --keep-open=yes to the command-line and see if it helps.

Not working.

Just close the browser and reopen it for the items to appear.

I did this before and it was not working for some reason but now it is working.

Why do you asking me for testing? On your setup there is no problem?