I'm receiving error message" merchant login id is invalid or acct is inactive"

I don't understand why a customer will get this message after he/she tries to pay with our jotform credit card option. How can this be remedied.

I have cloned your form and I can see it works fine, you could also test my cloned form here: https://form.jotformpro.com/71156167880966 

You could test using this payment info:

- Credit Card Number: 4242424242424242

- CVC : 123

- Valid Expiration Date

  *Later than the current date

I would suggest you to check the API info you're providing too, this error happens usually when your info has been wrongly entered or there is a missing part of it.

Here's also a link from Authorize.net support that you can check about it: https://support.authorize.net/authkb/index?page=content&id=A415 

Kevin G,
I could get your cloned form to work but not the actual form on our
website. I tried both the fake card # you provided and my own card #.
What else can you suggest? still not working.
Cynthia High / California Tour Lines
...

The reason why the fake credit card did not work on your form is because you need to set your integration to sandbox mode. 

While testing your form I can see the same error as well, no matter if I try with the embedded version or the direct link; however, as explained above, there may be something with the API info provided that is incorrect, you could contact Authorize.net support and make sure your account has been properly set up and your API info does not need any additional setting. 

You could also give  a try with the sandbox mode activated on your form, here's a guide with more details about it: https://www.jotform.com/help/221-How-to-Test-Authorize-net-Payment-Tool-on-Sandbox-Mode