I created a new blank project and tested a http request which worked.
Then I tried the same request on our app and it failed. I compared the config.xml to see where it differed and I didnt really see anything.
I then found this iOS10 http requests blocked? and it gave me a push in the right direction.
I didnt want to remove WKWebView so I tried updating it and it worked without issue.
The main indicator is that it fails as soon as you make the http request and it gives a undefined and nothing else.