Error message “parsererror”

Hello, I used 3 elementor contact form for Brevo integration. The first 2 work fine, however, when I connect the 3rd contact form, it no longer works and it displays the error message “parsererror” for all 3 contact forms.
However, when I am connected as an administrator, the forms work fine and arrive in the Brevo list. This “parsererror” error message only displays for non-connected browsers and the contacts will not arrive in the Brevo list.
Can you give me a clue to resolve the problem? THANKS !