I have the same error trying to publish http://lc4mkm.xara.hosting/orientdiary3a/orientdiary-2b1.htm which I have never had since it was created in 2017. The whole website can be viewed in Xara Designer Pro X 17. But when viewed through any browser the Error 404 is seen.
Has anything changed on your computer since the last successfully published update to your website which appears to have been in December 2024.
In the Web properties dialog which option have you used for publishing the website, see image below?
If you use the Export website option to 'publish' the website to a folder on your PC, this must be inside the Documents folder, not on the Desktop, open the folder and double click on index.htm can you open all the pages of the site from their links in the pages?
. . . . I do see a folder that does not belong to this site. Happened when I split the site into two. I will delete it and get back to you. . . . . That didn't work and yes as far as I can make out the optional subfolder is in the same location.
How did you split the site into two and are both parts one or seperate projects in Web Designer?
In the Xara Control Centre which image below does the folder structure look like:-