I start up MSFS and get error messages in the main menu that I have to check MY internet connection, no connection to servers… my internet connection is absolutely fine! I am writing this from the very same PC as MSFS is running on.
EDIT: Speedtest gave me this results: 260 Mbps Down / 54 Mbps Up / Ping of 6 ms
…I hope this is enough for MSFS 
Is there a way to see what MSFS servers are doing right now?
There’s already another thread about it…
Same is happening here, in the Washington DC region. I tried switching to offline mode but it won’t render all of the airport details.
Same here. Right in the middle of making a video too 
Hello! indeed, there is a service outage, make sure to follow this page as we are closely monitoring the activity: Online Services Monitoring
Hello all! There is an outage that the team is aware of. Please see:
Your may also participate in:
https://forums.flightsimulator.com/t/online-services-are-unreachable/525984