If the site operates from HTTPS, you will need to prefix HTTPS:// to the domain part.
If the site operates from a sub-directory of the domain, it will need to be reflected in the path of the URL
The back office system of ePDQ tells you what errors have occurred, i.e., looking like “unknown order/0/r,” which you can look up in the integration guide.
We would avoid dynamic template configuration as there is usually a lot of work around it.
You’re best testing all of this in the “test” gateway first, but that you must recreate all settings on the live and repeat testing.