dynamics nav problem help me

when i try to open dynamics nav 2015 this message show to me:

11.png

Hi Ahmed,
Looks like you tenant has been unmounted. You should contact your system admin (or whoever installed it) about this.
If that’s you, then you need to looking into your setup. If you’re not running multi-tenancy (every install is by default multi-tenancy - but with only a default tenant in the same database) then you need to check your server configuration.

Hi Ahmed,
Did it help, have you solved the problem?