Different setup/requirements: 2020 TU8000 CANADA 
I can only connect via web browser to my UN75TU8000 (Canada model) from ONE host IP - all others are denied.

To get any IP response from the TV via browser I had to do the following first:

Sign in to a Samsung account (Developer)
Enable Developer Mode setting to ON (12345 in Apps UI)
Set ONE specific host PC IP address in Developer Mode enable window
Power ON With Mobile  in EXPERT Settings turned ON
IP Remote in EXPERT Settings Enable

Also need to "Allow" access when prompted on TV.

With the above I can access via web browser ONLY by going to http://192.168.8.140:8001/ (see output below in next post)

http://192.168.8.140:8001/api/v2 or V3 or ms/1.0 all produce a 404 error.

Accessing from any host other than the one specified in the developer window will produce a 401 error (Unauthorized).

With CURL, I can launch an app from any host IP like this:

curl -X POST -i 'http://192.168.8.140:8001/api/v2/applications/111299001912' (opens Youtube)

Still trying to get it going with Homebridge (Hoobs) - not getting any promt on TV yet for access.
