If a virtual machine contains virus information, an anti-virus agent in the firewall might detect the virus data and stop the connection during replication.
When you reconfigure the replication and start a full sync, the replication stops in the same data block with the virus information in it unless the virus data has moved on the disk. Clones of the disk fail, but other virtual machines of the same size and configuration from the same host replicating to the same destination datastore replicate successfully.
Remove the virus information from the replicated guest to avoid replicating virus information.
Make an exception in the anti-virus rules in the firewall to allow the replication to proceed.