Issue to connect High Availabilty Grafana with MysqlDB

Hi here’s my problem Grafana-server service doesn’t start when i configure mysqldb as database.
It starts well when no database filled in grafana.ini

I’d like to start Grafana Server on 2 servers (high availability infra) on same db (located on dedicated DB Server).

Here’s the steps i performed to end with my error:

1.create db grafana and grant grafana_user on Dedicated DB Server.
Telnet from grafana to DB ok on port 3306

2.fill grafana.ini as follow

type = mysql
host = 10.126.x.xx:3306
name = grafana
user = grafana_user@10.126.x.xx
password = xxxxxxxPassword

3.grafana server failed to start with following error messages :

Sep 30 11:07:35 FRSLZABGRA01 grafana-server[11829]: t=2020-09-30T11:07:35+0200 lvl=info msg=“Connecting to DB” logger=sqlstore dbtype=mysql

Sep 30 11:07:35 FRSLZABGRA01 grafana-server[11829]: t=2020-09-30T11:07:35+0200 lvl=info msg=“Starting DB migrations” logger=migrator

Sep 30 11:07:35 FRSLZABGRA01 grafana-server[11829]: t=2020-09-30T11:07:35+0200 lvl=eror msg=“Server shutdown” logger=server reason="Service init failed: migration failed: failed to check table existence

Below the versions of my components :
grafana 7.2
Centos7.8
mysql 5.7

Do you have any idea where i made a mistake ?