Sometimes we will get the following error, while trying to start nginx…
[emerg]: bind() to 0.0.0.0:80 failed (98: Address already in use)
Then it means nginx or some other process is already using port 80. We can resolve this problem by the following steps.
Step1: Kill the process running on port 80
fuser -k 80/tcp
Step2: Restart nginx service
service nginx start