Not working with LibreOffice 7.5 linux

I have LT premium.
I’ve tested with LibreOffice 7.5.9 and LibreOffice 7.6.4 in fact.
I followed the guide here: How To Enable LanguageTool on LibreOffice: Step by Step

I don’t have Lightproof on my LibreOffice version, apparently, so the problem can’t be due to that:

Everything seems fine, but… Nothing happens: LT doesn’t show the mistakes, and no indication why it doesn’t work (no error message).


SOLVED! LT server was wrong: it’s NOT for premium version.