Dear,

There is an module available for your requirements. Which can directly send email from website contact us form, whenever users fill the form and send them.

Module link is-

https://apps.odoo.com/apps/modules/11.0/website_send_email_contact_form_spt/

Thanks.

in odoo 16 when you create a contact form and want to receive an email once a customer fills out the form, the email is not sent. I have ensured that the action required is to send an email once the form is submitted, verified that the email it is sent to is correct and it's still not working.

I have even recreated the whole form twice with exactly the same problem. Does someone know what else I can do please ? 

When doing testing on the form. It still is not sending e-mails to the pre-defined inbox... It did it before when creating the site but now this is not working

That still does not work in odoo 17, what a pain in......

Is there something else to do in a hidden corner to make this "contact us" send email work?

Or some kind of background situation where is was not updated properly?

In odoo 16, go to editor mode​​, select submit​​ button, in the right panel, go to Form > Action​​, choose send an E-mail​​, that's it!

The contact form creates new leads (or opportunities depending on your settings). It does not send emails by default.