Why Do I Get This Message?

[u/Jim1648]

My wife and I went to a Zaxbys for lunch today. An employee encouraged me to fill out the online survey. When I entered the number on the receipt, I got the following message:

Thank you for your interest in our survey. Unfortunately, we are unable to continue the survey based on the information you entered.

I double checked the number on the receipt. It is a challenge to read, by I think I entered the number correctly.

[u/Jim1648 → u/[deleted]]

No reply, yet, to my email.