I get messages from Builders ALL the time — just today on LinkedIn — saying they set up their destination and got an error when they clicked Check Connection.
The Check Connection button does NOT check everything about a destination, only that it is reachable. According to an SAP Note:
“The Check Connection does not guarantee that a backend is operational. It only verifies if a connection to the backend is possible from network perspective.”
Any code other than 500 is considered successful.
P.S.: 401 vs 403 — For debugging, it is important to know the difference between 401 and 403 error codes. 401, even though its message is “Unauthorized”, means that the user was not authenticated. 403 means the user was authenticated and their identity is known, but that they do not have permission to the resource. So when you get 401 for a connection to SAP Business Accelerator Hub, it is because your API key is not being sent — or not being sent in the correct way — and therefore the site does not know who you are.