It might be late, but for any other person who may get such an issue in future, for any connections you want to make to the server (in this case the machine that hosts the web application, regardless if it is iis or xampp) you need to allow connection or traffic through the specific port that will be used in the firewall
1. Go to Windows Firewall -> Advanced settings
2. Click Inbound Rules -> Then New Rule
3. Select Port -> Next
4. Specific local ports -> Add the Port you want to allow
5. Allow All Connections
6. Enter a name and a description for to help you remember later on
and you Done