RSVP won't add guests

When we try to add a guest to the list, it says it added them fine, but then when we pull up the attendance list, the person is not there, also tried to import an excel file, and it said 1 row imported successfully, but the same issue still.

erikaandbrendan.com/rsvp

I have been trying to add myself, Brendan Shurilla, but it won’t take it.

https://www.ads-software.com/plugins/rsvp/