Database error on web interface

[gdelabre]

Dear Zabbix forum,

I would like to ask you about following problems.
I have installed Zabbix(4.0.9) monitoring on virtual machin on centos 7.6 with this database (MariaDB in mySQL) but Zabbix web Frontend tell me this error:
The frontend does not match Zabbix database. Current database version (mandatory/optional): 4000000/4000003. Required mandatory version: 3040000. Contact your system administrator.
I do not understand this error, everything seems good to me, so my question is:
What are the different errors that can cause this error?
Thank you for your answers

[Atsushi]

The version of Zabbix server is 4.0, but the version of Zabbix web front end is 3.4. Match the web front end version to the Zabbix server version.

[gdelabre]

It's works,
Thanks for your help