System.isHostReachable sometimes return wrong value

Hello,

to check if a VM is after deployment realy accessable via network i use the method "System.isHostReachable(IP,1000);".

But sometimes this function returns false although the Host is reachable by vRO Aplliance, Client and all other comuputers.

Is there a known problem with "isHostReachable" or has someone the same problem or solution?

best regards,

Mike