Rest Api V1 Callout

Running ERP Epicor 10 version 10.2.300

Currently, I am attempting some HTTP callouts using the Rest API V1 and so far the callouts seem to work locally using localhost but not externally.

Using localhost it works perfectly
Documentation: https://MyAppServerHost/MyAppServerInstance/api/v1/Erp.Bo.CustomerSvc/List
Actual: https://epicor10/ERP102000/api/v1/Erp.Bo.CustomerSvc/List

Calling through browser results in “This site can’t be reached”
Documentation: https://appserver01/2017R/api/v1/Erp.Bo.CustomerSvc/List
Actual: https://epicor10.test.com/ERP102000/api/v1/Erp.Bo.CustomerSvc/List

Do you own test.com? or is that just an example of what you are using?

Just an example I am using,correct.

Is your external IP punched through your firewall and mapped to the Epicor server on port 443?

Yes my public ipv4 is covered by the specified range. Will double check on port configuration.

Is your SSL certificate valid to 2 different domains

https://epicor10/ and https://epicor10.test.com