The following url is not valid , when publishing infopath 2013 to SharePoint 2013

I have a SharePoint server farm and working sites, I created a form library and trying to publish a simple InfoPath form to the library but getting error:The following URL is not valid: http://servername

Environment is Server A is running Domain, Server B is running everything else. SharePoint 2013, SQL 2012, Office 2013

Solution already tried:

1-     Site is already at root level.

2-     Create host file entry and test with 127.0.0.1 but no luck

3-     Tried with DNS entries New Alias (CNAME) and New Host (AAA). no luck

4-     Added trusted site. no luck

5-     Allowed verbs (PUT) in IIS but no gain.

6-      Reset Form ID, publish again, no gain.

7-     Several reboot and IISReset.

8-     Tried adding this in my web.config but it took whole site down ( I was not sure if it should go in web.config but I just tested it anyway)

When I try the same InfoPath form in another single server environment, it works. Any advice on what else I should do to make it work in this 2 server environment? Thanks.