I'm just trying the very simple example provided at this URL: https://developer.ebay.com/Devzone/XML/docs/HowTo/FirstCall/MakingCallXML.html
Perl is setup to use SSL and I've verified by requesting https:example.com and getting a good response.
It isn't an issue with any of my ebay tokens/devID/appID/cert... verified by getting the same 500 response even if all of these values are empty.
I'm working on wamp64 development server, is the problem localhost related?