When users are out of a known or trusted location and required to MFA to sign in or access Office 365.
You may lock down the firewall on to the EOP IP addresses so that spammers can't send through that port. Using desktop email programs will make you more productive and your email will always be available, even offline. Office 365 MFA and the Apple Mail app for iOS concern We ourselves and several customers using Office 365 have noticed a recent issue with the Apple Mail app for iOS when Office 365 MFA is enabled. Make sure the Deleted Items, Drafts, and Sent Items folders (and any other folders you want to access in Thunderbird) are selected and then click Subscribe. Right-click your account name and click Subscribe. You can continue to have your inbound Internet mail delivered to it. This will make it less confusing if you also use webmail or another email client to access your Office 365 email. Open a different IP address for connections between Exchange Online Protection and on-premises Exchange, assign a DNS name hostname to it like, and run the Hybrid Configuration Wizard to change the on-premises SMTP endpoint so When users are externally they require to enter MFA to sign in or access Office 365 resources. Hybrid SMTP mail between on-premises and Exchange Online Protection should never go through any third-party message hygiene or relay server, appliance or cloud service. Office 365 MFA and the Apple Mail app for iOS.