We are tracking several massive outages across the Internet that may be affecting your email services or other applications. Currently there is an Azure DNS issue (just like with us, it's usually DNS) that impacts M365 and there is an issue at Amazon AWS as well.
If your mail is hosted on these platforms and you have an active subscription to ExchangeDefender, remember that ExchangeDefender Inbox was built for moments such as this for organizations that cannot afford to be down. Just go to https://admin.exchangedefender.com login and click on Inbox - you'll have the ability to access your last 2 weeks of messages and send/receive email in realtime.
No matter which of these cloud outages are affecting you we know how it feels and hope your services are back at 100% ASAP. In the meantime, we got you.
P.S. ExchangeDefender does not use AWS or Azure at the networking core for any critical services. Any messages that are queued and waiting during your outage will be delivered by ExchangeDefender when your tenant/services are back online automatically.