[Koha] Koha Opac and Staff Client is not working

[Ashok Francis]

Dear All,

I am using koha 17.03 version in ubuntu. I am getting the following error
after restarting the apache.

root at GSS-LIBRARY-SERVER:/home/gss-library-server# sudo service apache2
restart
 * Restarting web server
apache2                                                [Mon Apr 02
13:52:52.249818 2018] [core:warn] [pid 12703] AH00111: Config variable
${instance} is not defined
[Mon Apr 02 13:52:52.249868 2018] [core:warn] [pid 12703] AH00111: Config
variable ${instance} is not defined
AH00558: apache2: Could not reliably determine the server's fully qualified
domain name, using 127.0.1.1. Set the 'ServerName' directive globally to
suppress this message
(98)Address already in use: AH00072: make_sock: could not bind to address
[::]:8000
(98)Address already in use: AH00072: make_sock: could not bind to address
[::]:8001

[fail]
 * The apache2 instance did not start within 20 seconds. Please read the
log files to discover problems


Now, I am not able to getting the library opac and staff client. Please
help me.

Ashok.
New Delhi