The "SOAP Fault: Invalid Credentials" generally means:
- You have used invalid First Data credentials. Kindly, recheck your credentials. Remember, the gateway password is not the same as the merchant password. You will need to login into your First Data merchant account > select your terminal > here you will find your gateway password. If, you do not remember your gateway password then, you can reset it on the same page. Remember to save after you click reset to save the new password.
- You are using TEST credentials in LIVE mode or vice versa. First Data issues separate accounts for TEST and LIVE modes and you cannot interchange them.