My site is falsely classified as malicious by Office 365 Advanced Threat Protection

Question

My website is getting flagged by Office 365 Advanced Threat Protection.

This is what a user sent me:

When I scan the website with Sucuri it seems like everything is clean. Screenshot below.

If this is relevant, the website was quite broadly flagged when I bought it 2 years ago. Since then, this is the first time I've seen the website flagged.

Is there any way to resolve this with Microsoft, or investigate the problem further?

Solution

Unfortunately at this time Microsoft does not have a global "Report a False Positive" feature which would allow your website to be scanned, re-assessed and marked as safe for all 365 users. There is however an option that your user can do and that is request from their IT department to add your site to their custom whitelist (https://support.office.com/en-us/article/set-up-a-custom-do-not-rewrite-urls-list-using-office-365-atp-safe-links-35dbfd99-da5a-422b-9b0e-c6caf3b645fa) which would work for that particular organisation and would bypass the issue of the false positive.