Try setting the From Email address in Forms > [Form Name] > Settings > Notifications to be the same domain as your website.
Also consider using a plugin like WP Offload SES, WP Mail SMTP or Mailgun to handle all the email for your site.
Try setting the From Email address in Forms > [Form Name] > Settings > Notifications to be the same domain as your website.
Also consider using a plugin like WP Offload SES, WP Mail SMTP or Mailgun to handle all the email for your site.