Same issue here, started in early January 2021. Running native windows bedrock server 1.16.201.2. I can connect locally but not from outside of my LAN. Ports are forwarding like they should as everything was working fine prior to the update at the end of the year. I even went so far as to create a new server instance on a different computer and a completely different router. Tried different ports too.. nothing.
It's working! Running a 1.17 image provided by marctv via docker on synology. I can now connect locally and remotely again.