CF6: Could not initiate Mail function

since few weeks visitors have the message above sending a cf6 contact form. the website owner gets no mail.
The text after sending confirms that the mail would be sended.
what's happened and how to solve?

joomla 3, php 7.4

if an email is sent to the visitor then something should be wrong with the email settings to admin

Misterious, site copied to another hoster works. I will check the settings but nothing was changed in the forms since years.

I am thinking about updating CF. Is there a function to take over the existing forms?

Hello
I cannot find out the problem.
The settings in the form looks well for me ( I am not fit in CF6)






But what I saw is, that in Joomla config I cannot send a testmail, too. Undepended PHPmail oder sendmail.

Is here someone who can help?

clear the "from email" and "from name" fields

Aren't this fields needed to have the sender mail and name? So the mail to Website owner will have name and mailadress from it's owner instead of customers data.

I have removed them and I have no error message now.


Peter