Depending on your Microsoft 365 setup, it might not be enough to only whitelist IPs. If that is the case, you should also whitelist the so-called envelope sender addresses (technical senders). Doing so only takes a few minutes and we have prepared a step-by-step guide to make things easy for you.
-
Log in to your Microsoft Defender with an administrator account.
-
Expand the Email & collaboration menu, select Policies & rules, and then choose Threat policies.
-
Select Anti-spam, followed by Anti-spam inbound policy (Default). A new dialog will open.
-
Towards the bottom of this dialog, select Edit allowed and blocked senders and domains.
-
Under Senders (x), click Manage x Sender(s).
-
Here, enter the Envelope sender addresses (technical senders) shown in the SoSafe Manager (Settings / Whitelisting).
-
Select Done to finish the process.
