LanguageTool doesn't work in Wordpress

LanguageTool extension (Chrome) stopped working on WordPress. I reinstalled the extension, cleared cache and rebooted the system, but the issue persists. How can I solve it?

Could you describe what exactly the issue is? Do you use wordpress.com or a self-hosted WordPress?

I use a self-hosted WordPress. The language check seems not to be activated, but it is. Please see the screenshot. No spelling mistakes are highlighted, however there are many in the text. It used to work, but suddenly stopped. The language I write in is Polish, and it has been set as one of the languages I use. Please let me know if you have additional questions.

Do you know which version of WordPress that is? Also, can you reproduce the problem with a free account on wordpress.com, or does it work there (it works there for me)?