Hello
the main k2 category menu brings to HTTP ERROR 500 page (J! 3.8.5/K2 2.8.0).
Enabling the error reporting to maximum or developer I get a blank page, nothing in code view too.
It should be due too many items in subcategories, but I set to 0 all the options in Category layout.
In log file I don't see any error.
Please, what can I check to fix the issue?

Can you try using the default template?

Thanks for reply Krikor, it was a plugin problem, sorry. I fixed disabling it.