admin_notices hook show message all admin pages after plugin activate

For do this you need to save in the db a value for remember that the alert was already showed.
Else you can try to llok on that https://codex.wordpress.org/Function_Reference/register_activation_hook. With this you can execute an hook only on the activate action of the plugin.

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)