To recover the loss, you need to choose from one of three options.
Ignore the loss and continue, even though some messages may be lost. You can use the subscription comparison procedure that includes the rs_subcmp program with the -r flag to reconcile primary and replicate data.
See also Replication Server Administration Guide Volume 1 > Manage Subscriptions, and Replication Server Reference Manual > Executable Programs > rs_subcmp.
Ignore the loss, then drop and re-create the subscriptions.
Recover by replaying transactions from off-line logs (primary Replication Server loss only). In this case, you are not ignoring the loss.