In Python’s flask framework, address already in use

This error message indicates that you have a process bound to the default port (5000). If you have run the same module before, it is likely that the process is still bound to the port.

First, use the port window to find the process:

sudo lsof - i : 5000

If nothing unexpected happens, after executing the above command, the port will display the running port: the number of 5000 process

Kill the executing process:

kill process number