Why are form submissions going to SPAM folder recently?

Form submissions have recently started going to the SPAM folder and can't seem to be white listed in Outlook. Do you know what might be causing this?

I would suggest you to follow this guide in order to properly set up your emails so the recipient mail service provider does not think it is a spam email: https://www.jotform.com/help/208-How-to-Prevent-Email-Bouncing-Related-Issues 

You would also mark the forms as not spam so Outlook will know they need to be stored in the inbox or other folder, here is also a link that will help you to avoid legitimate emails to be marked as spam: https://askleo.com/how-do-i-stop-outlook-com-from-putting-legitimate-messages-in-the-junk-mail-folder/ 

If the problem still persists, you could also set up your custom sender by using the SMTP method, here's the guide: How-to-Setup-SMTP-for-a-Form

This way you will have more control over the sender info since it will be from your server.

Hope this helps.