Fixing tagManager AJAX Pagination That Falls Back to 404 Pages

The donor described a tagManager setup where the first filtered page worked, but deeper URLs such as ?page=2&sortby=price&sortdir=asc fell into 404 behavior once AJAX and pagination started interacting.

What usually breaks

• AJAX state and public URL state drift apart
• the backend expects one route shape, while the frontend constructs another
• pagination links lose filter parameters or produce malformed combinations

Why page one can be misleading

Page one often works because the base route is valid. The break appears only when the listing has to preserve both filter state and pagination state at the same time.

How to stabilize it

Make one layer responsible for URL generation. The frontend should not improvise routes the backend never agreed to parse. Once filter parameters, sort parameters, and page numbers all come from one predictable rule, these 404 loops become much easier to avoid.