Rest API called via Azure Gateway throws Bad Request Error(400)

Question

I have a Rest API which is taking a token as its parameter in the URL. When I Call this end point through Azure gateway, from Postman it is giving a Bad Request (400) error. But if I call the end point directly, its working fine. I checked the No of characters in the URL . Its < 2000 chars. And we are not using Consumption tier. I read in Basic tier we can have 10K chars in the URL ? Is there anything else I am missing here