Don’t receive e-mails when form submitted

I am desperate for help as have spend hours trying to solve this with no avail.

I used wpforms lite and worked just fine as received the e-mail when contact form was completed and submitted on website. I then upgraded to the pro version and now I don’t receive the e-mails. I created a fantastic form but when I submit it from my site I don’t receive an e-mail notification with details of what was submitted.

I have tried to set-up to send via SMTP by using various plugins (Postman, GMail SMTP etc) but after following all the steps it says URI mismatch each time.

I have also tried suggestions as per this link but could also not get any of them to work:
https://www.wpbeginner.com/plugins/how-to-send-email-in-wordpress-using-the-gmail-smtp-server/

Am I doing it all wrong or is there another issue like theme I am using or my domain host?

Any help will be appreciated as currently wpforms is useless for me and really enjoyed building the forms.

Thanks,

Handri