Seems that the issue occurs when the available languages for subtitles on youtube doesn’t match the name of the language on Lingq. Therefore it will display the “Subtitles are not available” message.
For example:
Lingq->Cantonese
Youtube->Cantonese(Hong Kong)
Lingq->Tagalog
Youtube->Filipino
This is more towards the employees and developers of Lingq that maybe they could take a look at this @zoran. Thank you!