I'm getting this error: "Please enter a valid social insurance number that is different from your spouse." even though it's valid

Hello,
I'm getting the above error, even though my spouse's SIN is valid and I already double checked that I am not entering any spaces or special characters. I tried entering [social security number removed] as her SIN and it works.
It keeps throwing the error whenever I try to enter her real SIN.

Can you please help?

Thank you