The cause often lies with the web host, either because they changed something or because you changed something yourself.

For example, I had two projects with the same web host with different domains, and one day I encountered the same problem with one of them.

In my case, in the WebSiteX5 settings for both projects, I used the email domain of the project where the contact form worked without errors.

     Domain A = Email Domain A = ok

     Domain B = Email Domain A = ok (problem with Email Domain B)

If the problem cannot be solved like mine, other users may have different solutions.

Danie, Thanks for your response.

I have 2 websites with 2 different email addresses.
On site 1 the contact form works fine, on site 2 it doesn't.
On both sites I use exactly the same settings, php version and are both hosted by the same provider.
On www.sitename.nl/admin the test both indicate "passed" and the emails are sent from both sites and both arrive properly.
I really don't understand why the contact form works fine on site 1, but not on site 2.
Does anyone have a solution?
Thanks in advance.

Now appers this in ADMIN section : [2025-06-07 10:16:07] Could not instantiate mail function.

The problem probably lies with your web host. Incomedia staff may provide more detailed information and tips starting Monday.

Please mention the name of your web host; other users may also be experiencing problems and may already have solutions.

I ran a test with the contact form on my website and my demo store, and both the email author and recipient received an email.

I'm using the Pro 2025.2.4 version for both projects. The web host is Hosteurope.