Website contact form going to junk email and how to find reason

[T-B-P]

Hi

With Exchange Online what is the best way to find out the reason my website contact forms are going to junk email?

Message trace report shows status as "FilteredAsSpam"

Thanks

[#2]

Check the headers, more specifically for the spf/dkim checks, and the X-Forefront-Antispam-Report header: https://docs.microsoft.com/en-us/office365/securitycompliance/anti-spam-message-headers

[#3]

@Vasil Michev 

Found spf in the header "15 received-spf None (protection.outlook.com: mywebhost.net.au does not designate permitted sender hosts)"

Couldnt find dkim or X-Forefront-Antispam-Report but "19 X-Microsoft-Antispam-Mailbox-Delivery" was there.