Sign in problem

I wish to buy your plugin but I need to test it before.

No problem if I use the login page of WP.

But I have a message error if I use the Sign in button of my website.

https://festivalphoto.ch/beta/. (connexion button).

After writing username and psw, and rush connect button, I have an error message.

“ERROR: the one-time password (TFA code) you entered was incorrect.

Strange because the system never asked me for TFA code !??

Any idea ?

The page I need help with: [log in to see the link]