Heads up to the greater IT & MSP community:
A major back haul provider for VoIP carrier services called bandwidth.com has been fighting a network affecting outage since this weekend. Many feel it's a similar style attack like was reported last week with VoIP.MS although that hasn't been confirmed.. You can read about that below:
If you are in the US & Canada while you may not have a direct relationship with bandwidth.com they do interconnect and service roughly 40% of the carriers across both countries so you may be affected anyway.
Bandwidth.com also powers Microsoft Teams Voice Calling Plans offered directly from Microsoft in US & Canada as well.
You can find out more about this from bandwidth.com's own status page https://status.bandwidth.com/
Also down detector is showing as well
You can use this site to determine if a number is handled by bandwidth.com's network https://www.carrierlookup.com/