Error message at checkout

[UnicornDesign]

I have an error code coming up when you go to check out. (Unknown error encountered, please try again).  I checked my error logs and these are some of the errors that were thrown.  I did check to make sure that my check out would accept any shipping and shipping will accept any payment.  Suggestions of where to go to find out what is throwing these codes?

[Basara]

Hello.
These warnings are all from the virtual_merchant_gateway extension. Please contact extension developer

[UnicornDesign]

ok - thank you

[UnicornDesign]

UPDATE:  found the issue - make sure you have the Merchant Number not the Account Number.  Thank you for your help!

[AGAEV25]

I'm getting the same error message. Are you saying not to use the API login ID and instead use the merchant ID? Only thing is we get the message when submitting orders but the transactions are going through on authorize.net's end, our merchant's end, and the bank's end. Weirdest thing, please help!!