wp-json/contact-form-7/v1/contact-forms/105/feedback 500

Hi

My CF forms won’t work. I recieve this error in console:

wp-json/contact-form-7/v1/contact-forms/105/feedback 500 jquery.js?ver=1.12.4:4

I get this error when I connect CF7 to Contact Form 7 Connector or Contact Form 7 MailChimp Extension. I know that those are 3rd part plugins, but maybe there is problem in CF7.

My site: https://israelitacticalkravmaga.com/

WP 4.9.9