Mariana,
These 404 error's are older pages, probably not in use anymore but still active on older pc's with saved links or in google index.

The best way to handle these is to create an .htaccess file for this.

I can explain it here but there are dosens of sites to tell you how to do that, probably better then i can.....

So check google on 404 error and find a site that suits your knowladge to create an .htacces file.

Best is to upload this with filezille, because x5 can't see it (it is a hidden file)

You can normaly also create one from your host with there control panel, maybe it is a good idea to check the FAQ of your webhost for this.

The .htacces file can be made with notepad, notice you don't set an extension! The extension is the actual text htaccess and the name of the file is empty so this becomes   .htaccess

for instance:

https://www.lcn.com/blog/beginners-guide-custom-404-pages/

or

https://www.siteground.com/kb/how_to_redirect_my_error_pages_to_an_url/

The general idea is to put this inside the file: ErrorDocument 404 http://domainname.com

in your case: ErrorDocument 404 https://piesebuldo.ro/

And how many 404 pages you have and where they are does not matter anymore, everybody that uses a wrong/old link will get redirected to you home page.

Best Regards,

Andre