Failed to start devlopment server — BindError: Unable to find a consistent port localhost

Question

Google-app-engine development server runs great yesterday, but when I try to start it today. It only shout out this Error.

I tried use lsof -i:8080 / <

Answer 1

Similar to what was posted, I had this issue and fixed it by altering the hosts file. The issue was with IPv6 addresses redirecting to localhost:

In my hosts file I had

127.0.0.1    localhost
::1          localhost 
fe80::1%lo0  localhost

And I commented out the IPv6 addresses to give

127.0.0.1     localhost
#::1          localhost 
#fe80::1%lo0  localhost

I'm not sure this is a viable permanent solution as I imagine it's important to have the IPv6 numerical addresses for localhost to be in the hosts file but it works for now until a proper fix is released.