DKIM
SECURITY RECOMMENDATION FOR ATERA.COM
The alerts from ATERA.COM are mostly being sent to Quarantine by Exchange Online (Office 365) and, if this is happening for us, it will be happening for many other companies using Exchange Online.
Whitelisting your domain under anti-spam policies doesn't overcome the problem (I've tried).
Looking at your public DNS configuration, you have not setup three important components of your DNS and Email infrastructure to assure customers of your email security: these are SPF, DKIM and DMARC.
Since you appear to be using Exchange Online/Office 365 for your email, it is a reasonably straightforward process and this would help all of your customers to be assured of the validity of emails genuinely sent from ATERA.COM
Additionally, if these are not setup it makes ATERA look unconcerned about cyber security (for those of us that have to be sensitive to these things).
Thank you.