How to consume 3rd party URL using REST and POST method?

Good day!

In Add/Update person page, I want to modify the delivered functionality that the source of EMPLID for my newly created employee will no longer come from PS_INSTALLATION. Instead, I will get the NEW Emplid from a separate system which is now handling the generation of Emplids. The owner of the separate system already provided a URL (http://TESTONLY/gateway/POST_api_spot-ids_v1/0.0.1/spot_ids/v1) that will be used so I can successfully connect to their system and utilize the Emplid. Every time I hit the SAVE button, my PeopleSoft system should send an empty message to separate system and they will respond me an Emplid via JSON ( {"emplid" : 23443} ). I tried the code below yet I am getting a zero return.