Plugin Error when Activated + Issue with Contact Form 7

Hi!

WordPress: 4.9.6–fr_FR
Theme: Ronneby (Premium theme)
All plugins, WP and theme are always updated to the latest version.
There are no other issues or errors on my web-site.

I want to use the plugins “CRM WordPress Leads” and “WP Freshsales” (for integration with the service Freshsales).

1) After installing and activating the “CRM WordPress Leads” plugin, this error immediately occurs.
……….
“L’extension a généré 230 caractères d’affichage inattendu lors de l’activation. Si vous voyez un message ? headers already sent ? (Les en-têtes ont déjà été envoyés), des problèmes avec les flux de syndication ou d’autres erreurs, essayez de désactiver ou enlever cette extension.”
……….
Screenshot here:
https://www.dropbox.com/s/5doxnn4er73g3nb/err2.png?dl=0

2) Also, after activating the “CRM WordPress Leads” plugin, all forms (created by the Contact Form 7) on my site have an infinite/endless loading/sending of the form. And there is no notification of successful sending. But the letters are coming.
This stops as soon as I deactivate the “CRM WordPress Leads” plugin.
Screenshot here:
https://www.dropbox.com/s/fz5gfag1ec6w5qo/err1.png?dl=0

3) There are also problems with the “Recent_note” Lead field. The Contact Form 7 plugin does not see it, and I can not edit it. If this field is enabled (for Freshsales), an error is displayed on the site.

I really need the integration (capture) of my WP-site with the Freshsales CRM service.
This is the only plugin, and I do not know how to fix these issues.

Thanks!