No emails after form submissions

Hi,

I’ve been using several form maker forms for years and it worked well in the past. I dont know when the problem raised for the first time but now without changing any settings neither the admin nor the user receives an emails about a submission. And it is the same for all forms not only one so it seems to be a general problem.

The submissions are logged in the database and the defined action after submission is executed but no email is sent,

The recommended gmail smtp plugin seems to be not suitable for us because we use our company email address @ml-software.com.

Any other ideas to solve the problem?
Where do I find wp email settings to check if there is something wrong?

Thanks for your support.

The page I need help with: [log in to see the link]