why is my API application Response 500 and 200 on postman

I have an application that is distributed across five servers and a basic Dev test environment on my dev environment all is working fine on my live which is distributed across five servers I try to talk to my API app and I get an error 500 while if I use postman or SoapUI I get 200.On the 500 error The error comes with one of the parameters supplied not recognised any suggestion on how to do further debug with detailed results please or solution if one has had an experience like this. Please not my API app was updated recently before then everything was working fine