Hi Deltona,
"We really should do an actual authentication test like we do in STM." - The authentication is not in our hands. If the SMI-S provider accepts any old credentials to login, there's not much we can do.
I completely agree about the "back button" to go re-edit the Provider. There is a way to edit the credentials, but it's outside of that flow. You have to go to Settings>Manage Storage Objects. Not the best, I agree, we'll look into making that better.
I've escalated your case with Engineering. Thanks for sending me the details.