Ah... I tried to optimize URLs a bit and changes this titles for tho HTML pages I have.
Now all records (articles) are returning "can't be found error" with a code error 2T252/2.

I tried to remove the URL settings or change it. The records are still showing the path of initially changed URL path. How should I repair this mess?

 

Disaster. Now articles aren't available anymore. Can't put a database widget as it's not available anymore... Prior this (I went after "let's see if I just re-create widgets again") "new article" option was not available anymore also. From the menus. It was than I started to suspect something is broken... How is it possible that after such a simple optimization, everything goes to hell!?

 

Try clearing your cache.

System > Settings > Support > "Something it's working correctly" > Next > First thing it does is clears the cache.

Thanks for the hint. I did this already. Also run all the task inside advanced config. Nothing helps. Now, I'm stuck completely.

Share the link to your site please.

PP. Also System - Support - System logs

I suspect that you have another misconfiguration, but it’s not really clear from your description. How did you change the URLs and what did you do exactly? The screenshot you posted has nothing with URLs. 

The best thing to fix this would be to open a support ticket and have someone with experience check it out directly on your site. Otherwise its all guesswork. 

What I would check: Go to the database overview. Check if the article database has a page assigned to it. If so, go the pages overview and check out that page. Does it have the correct permissions? What FURL was set for it? Can you access that page with that URL? Open that page’s content and check what is going on there. For a non-pagebuilder-page (as shown in the screenshot) that would be visible in the content tab. What’s listed there? And so on and so forth.  It needs to be narrowed down. Just the fact that article can’t be loaded anymore doesn’t really tell us why.