Rails: Address already in use - bind(2) (Errno::EADDRINUSE)

You need to use kill -9 59780 with 59780 replaced with found PID number (use lsof -wni tcp:3000 to see which process used 3000 port and get the process PID).

Or you can just modify your puma config change the tcp port tcp://127.0.0.1:3000 from 3000 to 9292 or other port that not been used.

Or you can start your rails app by using:

bundle exec puma -C config/puma.rb -b tcp://127.0.0.1:3001

To kill the puma process first run

    lsof -wni tcp:3000 

to show what is using port 3000. Then use the PID that comes with the result to run the kill process.

For example after running lsof -wni tcp:3000 you might get something like

    COMMAND  PID  USER   FD   TYPE DEVICE SIZE/OFF NODE NAME
    ruby    3366 dummy    8u  IPv4  16901      0t0  TCP 127.0.0.1:3000 (LISTEN)

Now run the following to kill the process. (where 3366 is the PID)

kill -9 3366

Should resolve the issue

you can also try this trick:

ps aux | grep puma

sample output:

myname           77921   0.0  0.0  2433828   1972 s000  R+   11:17AM   0:00.00 grep puma
myname           67661   0.0  2.3  2680504 191204 s002  S+   11:00AM   0:18.38 puma 3.11.2 (tcp://localhost:3000) [my_proj]

then:

kill -9 67661