ssl_error(406)

Using HTTPAPI v1.41 on V7R3 of the operating system.

I can connect to this API successfully using POSTMAN on my PC with the http authentication headers supplied by the web service.
I have verified the HTTP Headers in HTTPAPI (I can see them in the debug file).

However, I'm receiving the following response (from httpapi_debug) when using http_get() within my program:

(GSKit) I/O: A connection with a remote socket was reset by that socket.
ssl_error(406): (GSKit) I/O: A connection with a remote socket was reset by that socket.
SetError() #44: CommSSL_read: read:(GSKit) I/O: A connection with a remote socket was reset by
recvresp(): end with err
http_close(): entered

I'm just not sure where to go from here.
I downloaded the latest HTTPAPI (listed as 1.42) but the CHANGELOG text member still appears to be 1.41.

TIA,
Greg