Error 500 al hacer submit con CF7

Hola,
me está dando un error 500 al hacer submit con Contact Form 7.

El contacto se crea bien en Holded y vuelca bien la información, pero el formulario de Contact Form 7 mantiene la rueda de proceso y en la consola del navegador salta un error 500 en el fetch de la invocación a “https://{DOMINIO}/wp-json/contact-form-7/v1/contact-forms/4623/feedback”

El error que me sale en log es éste:
AH01071: Got error ‘PHP message: PHP Fatal error: Uncaught Error: Call to undefined method CRMLIB_HOLDED::create_lead() in?/var/www/vhosts/{DOMINIO}/httpdocs/wp-content/plugins/formscrm/includes/formscrm-library/class-contactform7.php:278\nStack trace:\n#0?/var/www/vhosts/{DOMINIO}/httpdocs/wp-includes/class-wp-hook.php(312): FORMSCRM_CF7_Settings->crm_process_entry()\n#1?/var/www/vhosts/{DOMINIO}/httpdocs/wp-includes/class-wp-hook.php(334): WP_Hook->apply_filters()\n#2?/var/www/vhosts/{DOMINIO}/httpdocs/wp-includes/plugin.php(565): WP_Hook->do_action()\n#3?/var/www/vhosts/{DOMINIO}/httpdocs/wp-content/plugins/contact-form-7/includes/submission.php(767): do_action_ref_array()\n#4?/var/www/vhosts/{DOMINIO}/httpdocs/wp-content/plugins/contact-form-7/includes/submission.php(103): WPCF7_Submission->before_send_mail()\n#5 [internal function]: WPCF7_Submission->{closure}()\n#6?/var/www/vhosts/{DOMINIO}/httpdocs/wp-content/plugins/contact-form-7/includes/l10n.php(147): call_user_func()\n#7 /var/www/vhosts/{DOMINIO}/httpdocs/wp-content/plugins/cont…’, referer: https://{DOMINIO}/formulario/

Hacéis un gran trabajo.
Muchas gracias.