Forums stopped displaying part way down list

My forums stopped displaying this afternoon. I'm getting server errors. I don't know what I've broken

• TypeError: Macro public:node_list_category :: depth1() error: XF\Util\Str::normalize(): Argument #1 ($string) must be of type string, null given, called in /var/www/sneaker-groups.com/src/XF/Mvc/Router.php on line 558
• src/XF/Util/Str.php:97

Читать далее...