Gateway credentials are not valid

Gateway credentials are not valid

I'm trying to setup authorize.net with a "trial/test" subscriptions account.
I get a message that credentials aren't valid...but I updated authorized.net and disabled old credential sin case for some reason they weren't working.  So, I created new credentials and they are perfectly input (manually typed once and copied/pasted twice).

I have enabled CIM (and we've used it with other apps).

But, it still doesn't work.  So, a couple questions:
1) Can authorize.net be setup in trial/test mode of subscriptions?
2) Is there any known issue with authorize.net currently?

Thank you in advance.  Cori