Website login fails using the Vision Web Browser Component

I have a Web Browser component. It loads a cloud based monitoring site for our ozone machines.

I can login to the site just fine from the Ignition client computers as well as from my own laptop using Firefox, Chrome, Edge, etc. I can even login to it while testing the component from Designer.

If I try it from any of our Ignition client computers I get "You must enter a username and password."

Even though the username and password are entered and correct.

I don't see any errors in the Console.

The likely explanation is that something about the web browser component is failing to validate with your external sites' backend, and that's ending up with a generic HTTP error that the page's frontend is displaying as "You must enter a username and password" - that is, the particular error message is a red herring.