Web Installer Error in Koha

Software error:

Access denied for user 'kohaadmin'@'localhost' (using password: YES) at /usr/share/koha/lib/C4/Context.pm line 790.
BEGIN failed--compilation aborted at /usr/share/koha/lib/C4/Auth.pm line 63.
Compilation failed in require at /usr/share/koha/intranet/cgi-bin/mainpage.pl line 25.
BEGIN failed--compilation aborted at /usr/share/koha/intranet/cgi-bin/mainpage.pl line 25.

Reason:
'koha' user doesn't have access to the koha database with the credentials supplied. Can you check the user and password you specified in the /etc/koha/koha-conf.xml file? (search for "db_scheme" and you'll see the database details below that)

In the file... /etc/koha/koha-conf.xml,  search , what password has been set and compare the same while you creating mysql db and grating all privileges.

<!-- ADDITIONAL KOHA CONFIGURATION DIRECTIVE -->
<!-- db_scheme should follow the DBD driver name -->
<!-- port info: mysql:3306 Pg:5432 (5433 on Debian) -->
<config>
 <db_scheme>mysql</db_scheme>
 <database>koha</database>
 <hostname>localhost</hostname>
 <port>3306</port>
 <user>kohaadmin</user>
 <pass>password</pass> {the password here should match with mysql db user password you entered at the time of grating all privileges}
 <biblioserver>biblios</biblioserver>
 <biblioservershadow>1</biblioservershadow>
 <authorityserver>authorities</authorityserver>
 <authorityservershadow>1</authorityservershadow>
 <intranetdir>/usr/share/koha/intranet/cgi-bin</intranetdir>
 <opacdir>/usr/share/koha/opac/cgi-bin/opac</opacdir>
 <opachtdocs>/usr/share/koha/opac/htdocs/opac-tmpl</opachtdocs>
 <intrahtdocs>/usr/share/koha/intranet/htdocs/intranet-tmpl</intrahtdocs>
 <includes>/usr/share/koha/intranet/htdocs/intranet-tmpl/prog/en/includes/</includes>
 <logdir>/var/log/koha</logdir>
 <backupdir>/var/spool/koha</backupdir>


as a root or dba
#grant all on <kohadatabasename>.* to '<kohadatabaseuser>'@'localhost'
identified by '<mysql-password-for-kohadatabaseuser>'

Now, you should be able to run the web installer.