I added an output of the headers:

SRG>D GET^KCSAPI
HTTP/1.1 415 Unsupported Media Type
CONNECTION: Close
CONTENT-LENGTH: 106
CONTENT-SECURITY-POLICY: sandbox;
CONTENT-TYPE: application/json
DATE: Wed, 07 Jul 2021 15:38:26 GMT
MS2-ERROR: MockRequestError
SERVER: nginx
STRICT-TRANSPORT-SECURITY: max-age=31536000; includeSubDomains
X-CONTENT-SECURITY-POLICY: sandbox;
X-ENVOY-DECORATOR-OPERATION: service.mocking.svc.cluster.local:80/*
X-ENVOY-UPSTREAM-SERVICE-TIME: 9
X-REQUEST-ID: 7deac252-b38a-430e-9931-e77a8b87bef2

Error has occurred <COMMAND> in SRG at 11:38 AM  Jul 07 2021
(now saving error/stack information)

Any documentation I can find containing this 'error' refers to making POSTs.  I'm doing a GET, so I'm completely baffled....

Currently, I am creating the file via Cache ObjectScript/routine and then ftping it over to the file share Or pulling the file from the file share via ObjectScript/routine and reading/processing it.

Because we will be moving our data to Sharepoint, I need a connection/transfer method that I can use in my routine in place of the ftp/sftp that is currently being used because Sharepoint doesn't allow the ftp/sftp of files.

We don't have that option in Cache yet.  (Getting ready to upgrade to 2017 - but checked, and it doesn't either).

%SYS>D ^DATABASE

 1) Create a database
 2) Edit a database
 3) List databases
 4) Delete a database
 5) Mount a database
 6) Dismount a database
 7) Compact globals in a database
 8) Show free space for a database
 9) Show details for a database
10) Recreate a database
11) Manage database encryption
12) Return unused space for a database
13) Compact free space in a database
14) Defragment globals in a database

Option? Q

%SYS>D ^VERSION
Cache for UNIX (Red Hat Enterprise Linux for x86-64) 2015.2.3 (Build 855_0_17370) 

I wonder if Canceling from that option in IRIS is the same as Terminating a Process in cache - risking data integrity issues with ab-ends...