"Unable to Process" error, Authorize.net shows as processing.

Submit donation form having some issues after making dev site live. When a user donates, an error shows up as "Unable to Process", but Authorize.net shows it as processing the payment. Site not receiving email that a user has donated.

Here is the link to the form page: https://www.lplearningcenter.org/donate/donate-now-page-link

I entered a donation and got an error message (but it didn't give me an error code - just a typed message as part of the donation submission:
Message was in two places - at the top - that donation couldn't be submitted see below. And then below my cardholder name it stated:
There was an error processing your credit Card. Please verify the information and try again.

I logged in to Authorized.net and found my donation plus the one made by Christopher Hajer for $1.00. When we had lots of fraudulent charges last spring, we set a fraud check that any $1 donation would be pending until I had reviewed it. So it was there waiting for me to approve or decline. Then a second fraud check we put in place was to hold multiple donations for the day until I approved (this was put into place because fraudulent chargers would redo a "donation" when the $1 didn't go through and just change the amount). So my donation tonight was also put in the pending section.

I went ahead and approved my donation and got notification, as the authorized person at the Center, from authorized.net that the donation was processed. Then I got an confirmation email via the online donation section (I assume because it was to me as the donor) that was in the format of an "order confirmation" (I will forward you a copy of that email). However, I did not get a copy of the donation information from the online donation form like I used to. This email was to tell me who donated, the address, purpose of donation and the other information (except credit card) that is put into the online donation form.

I hope this additional information helps. Hopefully there is some coding that can be done that gives a message your donation has been submitted (if it has all the required information) and that also triggers the email to me with the donation information. Then if I don't get notification from authorized.net of the donation, I can log on and see why it is pending.

We also tried turning on debugging in the Authorize.net plugin, but that is not working. In the instructions from an issue prior, it said to add "&debug=1" to URL.
https://www.lplearningcenter.org/wp-admin/admin.php?page=gf_settings&addon=Authorize.Net
becomes
https://www.lplearningcenter.org/wp-admin/admin.php?page=gf_settings&addon=Authorize.Net&debug=1
When we do this, the page does refresh, but no settings are available. We are using Gravity Forms 1.6.9, Gravity Forms Authorize.Net Add-On 1.3. We turned off all other plugins and doing that did not change the behavior. Has this switch changed? Also, is there anything else we can do on our end, troubleshooting wise, to get additional information that might help resolve this?

We also did a few more tests. One had an error in the address for a legitimate credit card, one was totally correct, one used a test Visa number. In all three cases the error was the same, <!-- Error: 33 -->.