If this sounds like your week
"An attempt was made to access a socket in a way forbidden by its access permissions."
This isn't your app and it isn't a normal "in use" conflict. Windows has *reserved* a block of ports for Hyper-V / WSL2 / Docker via WinNAT, and the port fell inside one of those excluded ranges. Nothing is listening on it — you simply aren't allowed to bind, and the error message tells you nothing about why.
Where tooling usually breaks
You search the port. Nothing is using it. It still won't bind.
`netstat` shows the port as free, so every "kill the process" tutorial is a dead end. The real answer is buried in `netsh int ipv4 show excludedportrange tcp` — a command almost nobody knows to run — and the fix involves reserving your range or restarting WinNAT. Hours disappear here.