Rest return 500 error

I have an application which is distributed across maybe 5 servers since it has over a thousand users at a time we had an upgrade to the application last week and I had an integration build that uses the REST service (  ##class(%Net.HttpResponse) but since the upgrade the integration has not be able to communicate with the application tried testing my URL through Postman and all seems ok but if I test direct  I get a 500 error anything that I need to check on please or any advice on how to check what's going on. I have used SoapUI with 200 result so as postman and swagger