Language dissapeared from the dashboard

Hi
Did you activate this filter: Filtering the content on backend side:
https://polylang.wordpress.com/documentation/setting-up-a-wordpress-multilingual-site-with-polylang/user-personalization/

That’s strange. I didn’t even touch it. I see that I can switch between languages there, but previously I was able to see both languages at the same time (mixed). Now the option of selecting all languages is inactive…

I didn’t understand if your problem was solved.
When you click on “Show all languages”, did you see your both languages?

No.

The thing is that I can’t click “show all languages”. It used to work, I still can see this option, but it’s not clickable. I can only click separate languages. ??

Could you test with:
* Your theme + Polylang + no other plugins?
If it fails, test with:
* Twenty Fifteen + Polylang + no other plugins?

Chrystl, unfortunately both tests FAILED.

What’s more, I noticed that I have no access to “categories” and “tags” in the Polish language. I can’t see them nor edit them. They are also not displayed in the blog.
See (you need to click <Filter Contents> )
EN: https://travelingilove.com/?lang=en#contents (it works)
PL: https://travelingilove.com/?lang=pl-2#contents (it’s not working)

* Twenty Fifteen + Polylang + no other plugins?

Could you confirm on your admin side that Polylang doesn’ t work correctly with Twenty Fifteen on your installation?
What is not working correctly?

EDIT: Please provide screen shots of your:
* language settings
* category list
* tags list
* pages list (Pages > all pages)

Please don’t cut the left menu and the admin bar on your screen shots. Thanks.

When I had a similar problem a language was not imported correctly. This is what helped me: Try to import a language you have never used and look if English is appearing again in your language list. Then delete both … the incorrect imported English and the language that you have just added. Now you can import English again. Maybe it is worth a try … at least it helped me when I couldn’t see a language in the backend that was already (incorrectly) installed.