401 Unauthorized API Response (and fix)

Problem/Motivation

I received the following error code after enabling debugging and not seeing any rates returned.

Client error: `POST https://onlinetools.ups.com/api/rating/v1/Shop` resulted in a `401 Unauthorized` response: {"response":{"errors":[@"code":"250002","message":"Invalid Authentication Information."]}}

The issue was that I did not enable "Rating" as a service in the API key setup on UPS. This is clearly documented on the home page of the module but I somehow missed this during setup and did some searching for the error but didn't find any results. So posting this here for easier future searches if someone else runs into the same issue.

Steps to reproduce

Add API information and go to checkout.

Proposed resolution

Read the documentation!

For the mods I wasn't sure how to categorize this so feel free to alter/close it.