Error 404 /80/_vti_bin/Webs.asmx - Sharepoint 2013 PDF check out and open option

I am attempting to restore the integration between adobe and SharePoint 2013 for check in / out. I followed this post here [Sharepoint 2013 PDF check out and open option ] and installed the PDFFIX.js

I now receive and error while opening files.

I inspected the traffic with Fiddler 4

I see a 404 on /80/_vti_bin/Webs.asmx. The issue is that address doesn't exist. The forward slash '/' should be a collon ':' because it's port http://[mysite]:80/_vti_bin/Webs.asmx

When I use an AutoResponder rule in fiddler to find / replace --- SUCCESS!

This is as far as I got. I'm going to dig in further but maybe someone has some more information before I waste even more time.