Receiving 404 for Recurly

I am trying to reverse proxy to recurly. But I keep getting 404. There does not seem to be much information to debug about the detail. I tried different proxy url and that works fine. But for some reason, the reverse proxy for recurly is not working.

As mentioned earlier, there does not seem to be a way to debug either.

P.S. I have added the required headers with Authorization and Accept. These headers work fine when used via HTTParty.