Getting this error with a user after Shift4 re-setup UTG on an RMA’d machine. All files in RPRO had remained the same. Issue was that client had typed in new Net API # and password and it was incorrect. We called Shift4, got a new one and reentered and it was all fine between the two after that.
The other reason for this error is that the shft4 pipe is not found. You can determine this by stopping the utg2 service and starting up UTGStand Alone, at the very top uin red color wil says PIPE NOT FOUND. This means Shift4 has not completed the setup process on their end. They will need to make sure the PIPE is created for this to work.