add new articles problem

hello,
i use your great plugin for a while,
but now i added some new articles to a category and a problem came up.
unfortunately the new articles do not appear in the sidebar i use
your plugin.
my widget logic code for this is:

is_single()&&
in_category(‘Περιβαλλοντικοί Ρύποι’)

any suggestions?

https://wordpress.org/plugins/widget-logic/