The error messages says its "network error" between source and destination cluster.
this could very much happen if you are replicating over WAN.
If there is a checkpoint created, snapmirror might start from that level. otherwise you have to start all over again.
Few things you can check before you start again.. (just to be sure...)
1, Snapmirror LIF status on Source and Destination.
2, Look for any packet loss in that network.
3, Cluster peer status,
4, Vserver peer status.
5, Destination volume size (should be same or larger than source)
6, Ontap version on source and destination cluster. (destination should be same or newer than source)
Robin.