Errors trying to yarn start

everything goes fine till I yarn start. I got this error:

yarn run v1.22.17
$ port-precheck 5000 5001 5002
Error: Required port [5002] is currently in use
error Command failed with exit code 1.
info Visit yarn run | Yarn for documentation about this command.

but infact port 5002 isn’t in use.

As the error suggests, port 5002 is in use. You have another node app or service running at that port and so there’s a conflict.

On Windows, the command

netstat -ab

will show you all ports in use. You need to validate that the port is in use and stop the service using it before attempting yarn start again.