[Plugin: WordPress Forms] Empty page on "Create new"

https://www.ads-software.com/extend/plugins/wordpress-forms/
When I press “Create new” button, plugin redirects to
https://www.website.com/wp-admin/post-new.php?post_type=form
and it’s empty, just blank white page (page source is empty too).

I’m useing this great plugin in several websites and its working just fine. I dont know why problem accured this time. Tryed disabling other plugins, fesh install of wordpress, nothing helped.

Thank you for any help.