Update: poking around a little bit and i see there is an ajax request on hitting the "add spouse" button and ufiles server returns an error 500. (error.png)
Also side note there is a vendor.js that fails to run due to mime-type, a handful of 404s, and like 11 console.log('j') on pageload. Seems like your developers need a test server that is not also the production server. (amateur hour.png)
Edit:
FYI your mime type issue is you reference "https://secure.ufile.ca/T1-2021/cli/vendor.js" as a script but that file does not exist and instead of issuing a server side 404 you issue a 302 and redirect to a "404" error page (https://secure.ufile.ca/errorPage.aspx?aspxerrorpath=/T1-2021/cli/vendor.js) but serve it with a header of 200. That makes the browser try to run your error page like a script. If you are not careful that is a potential security issue. I suspect you take security of the application repos very seriously but now your application is trying to execute scripts from locations that may not be as well controlled or monitored.