Membership 2 Pro Authorize.net payment error

I'm trying to test out a membership transaction after having upgraded from Membership to Membership 2 Pro. After I enter my credit card info, I get the following error:

"Payment failed due to CIM profile not created: User authentication failed due to invalid authentication values."

Things I've tried:
Verifying API Login ID
Generating a new Transaction Key
Clearing Cache

Please advice. I'm really anxious to get this up and running again.