Created a category blog menu item pointing to a category with 3 articles. Go to that menu on the front end and I get 500 - ERROR: Invalid Article parent ID (12)! (ERR 410)
Tried pointing the menu item at a different category and it worked OK. Removed problem category; created now one; changed articles and menu link to this new category - and it still didn't work.
Have tried all the usual things: - clearing browser cache; different browsers; 'rebuild' on menus and categories; 'Fix' on the database. After much experimenting, I have 4 categories: 2 display correctly in a category blog and 2 give the error above. Doesn't matter which articles are in the category. So far, no newly created categories will work - the 2 that do work are original ones. (... but so was the first one that didn't work.)
Someone suggested an asset issue and recommended a tool to fix it. Bought it and it did find and fix a few problems but made no difference to my problem.
Tried... adding new category, point article to new category, remove old category (and empty trash), point article blog menu item to new category, check 'ACL Manager' extension for no asset problems, empty browser cache...
Try the front end and exactly the same error except that the id has changed to that of the new category!
I've no idea what to try next!
Any help appreciated...