Form is not accepting an address

I have a couple customers who are married and live at the same address who have tried to register for a class on my website using jotform. When the wife submitted her information it was accepted and when the husband submitted his information and tried to hit submit it told him that no duplicate submissions are allowed for the address. I have gone through the settings in the form and I can't seem to find anything that would prevent any duplicate submissions except for the email address and phone numbers. 

I checked your form. You have enabled "Strict Check". This checks the Cookies & IP address of the user.

So, most probably, your respondents have used one browser or IP.

You can adjust the "Unique Submissions" field from the settings. In order to avoid this issue, you should select "No Check". Then you can ask your users to submit the form again.

Let us know if you need any further assistance.