FATAL ERROR DB Error: insufficient permissions

Hello, I am new in this forum as well as new to use Elastix, I recently restore from my backup file, however during the restoration, the error message of:

“INFO: restoring component endpoint/ep_db…
FATAL: endpoint/ep_db: failed to read list of MySQL schemata: SQLSTATE[28000] [1045] Access denied for user ‘root’@‘localhost’ (using password: YES)” is appeared and the restoration is not successful.

After the unsuccessful restoration, my elastix got error when I access to PBX Configuration page.

Before I posted to ask for help, I try to resolve follow by the some solution had posted in this forum too, but still no luck.
The issue that I am still cannot figure out is I could not see any database and the root access also denied to show any MySQL database.

Please kindly help me and here is the error:

FATAL ERROR
DB Error: insufficient permissions
Trace Back
/var/www/html/admin/libraries/db_connect.php:75 die_freepbx()
[0]: DB Error: insufficient permissions
/var/www/html/admin/bootstrap.php:85 require_once()

and much more error message…

here is my detail of Elastix:

Kernel
Linux(x86_64)-3.10.0-229.14.1.el7.x86_64

Elastix
elastix-4.0.0-1
elastix-a2billing-2.2.0-0
elastix-a2billing-callback_daemon-2.2.0-0
elastix-addons-4.0.0-5
elastix-agenda-4.0.0-3
elastix-asterisk-sounds-1.2.3-1
elastix-email_admin-4.0.0-6
elastix-endpointconfig2-4.0.0-3
elastix-extras-4.0.0-3
elastix-fax-4.0.0-2
elastix-firstboot-4.0.0-3
elastix-framework-4.0.0-18
elastix-im-4.0.0-2
elastix-my_extension-4.0.0-2
elastix-pbx-4.0.0-8
elastix-portknock-0.0.1-0
elastix-reports-4.0.0-6
elastix-security-4.0.0-4
elastix-system-4.0.0-11

RoundCubeMail
RoundCubeMail-0.3.1-12

Mail
postfix-2.10.1-6.el7
cyrus-imapd-2.4.17-13.el7

IM
openfire-3.7.1-2

FreePBX
freePBX-2.11.0-26

Asterisk
asterisk-11.25.0-0.el7.centos
asterisk-perl-1.03-0
asterisk-addons-11.25.0-0.el7.centos

FAX
hylafax-4.3.11-1rh7
iaxmodem-1.3.0-0.el7.centos

DRIVERS
dahdi-2.10.2-0.el7.centos
rhino-0.99.7-0
wanpipe-util-7.0.14.3-0

Elastix is a dead system. That’s a problem.

The permissions on the database are wrong.

In normal FreePBX, the root user doesn’t have a password for localhost. You’re using one.

In case you want to migrate to a supportable system:

https://wiki.freepbx.org/display/PPS/Elastix+and+PBXinaFlash+to+FreePBX+Distro+Conversion+Tool