IWS and REST GET HTTP 405

When calling a REST GET, I'm receiving an HTTP 405 (Method not allowed). Additional info below, but we are on 7.1 and IWS is V2.6. The much more complicated POST we wrote, in the same SRVPGM, works fine to eliminate other connectivity issues. Any thoughts?

URL used in Postman... http://<servername>:50010/web/services/cac/?orderNumber=ABC123

General Tab in IWS
Base resource URL:

http://<server>:50010/web/services/cac



Methods Tab in IWS
Procedure name:

CAC_RETRIEVE

HTTP request method:

GET

URI path template for method:

/{orderNumber:\w{100}}

HTTP response code output parameter:

httpStatus

HTTP header array output parameter:

httpHeaders

Allowed input media types:

*ALL

Returned output media types:

*JSON


Input parameter mappings:

Parameter name

Data type

Input source

Identifier

Default Value

eCommOrderNo

char

*PATH_PARAM

orderNumber

*NONE