The problem is; that enhanced webserver. (a.k.a. Complex WebServer) does not serve web pages over http.
The attachment was just for reference. But I do believe that the 702 errors have something to do with it. Input 0 and Output 0 are defined within the locked portion of "Web Server Application V350.vlp" which i got from here. https://unitronicsplc.com/support-tools-and-applications/
I'm using the vlp file as a base, which is recommended, and changed the hardware. But maybe the v1210 is incompatible?
According to this, it should be possible somehow. https://unitronicsplc.com/wp-content/uploads/2015/12/Unitronics_products_EU_low.pdf
"Web server: Use built-in HTML pages, or design complex pages to view and edit PLC data via the Internet"