Garmin have released an FAQ about their current situation.
https://www.garmin.com/en-US/outage/For your education, here are some alternative, possible more accurate, answers.
1. As a consequence of a corporate decision to keep all our customers dependent on our servers for anything but the most basic functions, your smart devices are stuffed until we can get it fixed. This decision is also the reason that we became such a compelling target for those greedy bastards ( the criminals, not us) that have the tech know how.
2. SOS remains unaffected due to a decision by someone to spend money on an alternative backup platform. We will not be giving him his job back, even though his disregard of profit maximisation means that we are not completely covered in shit.
3. You’ll have to wait to back up your data, because even if we could ship an update to allow Garmin Connect to work off line, we’re not yet ready to throw in the towel and let you be independent of our servers.
4. We don’t know what’s happened to your data. I mean, the baddies (the criminals, not us!) shut us out of the system, so it stands to reason that they shut themselves out as well. We don’t know this though, and won’t until we can get access to our systems again.