Mails from whitelisted domain mails still getting quarantined with quarantine reason: "High Confidence Phish"

Hi all,

I and my team are trying to carry out the Sophos Phish Threat V2. Our environment is Microsoft office 365 cloud-only. I have followed all the steps to whitelist the domains and the IP addresses, but still, the emails are being sent to quarantine.

Is there anything I am missing?

Thank you for your anticipated response.