Push notification does not work with fortitoken mobile

I have configured one of my internet connection to use push notification. 

I have created the rule via Cli:

config system ftm-push

 set server-ip X.Y.Z.66

 set status enable

end

I enabled FTM in the interface.

Every time I try to connect no push message arrive but only a request for token.

In the log i find:

Push message for user johndoe sent failed. Login ip is X.Y.Z.W and login virtual domain is root. Message id 1574522335.

Regards,

Graziano.