freebsd stable - May 2016 - ssh error: Fssh_packet_write_poll: Connection to 192.168.0.5 port 22: Cannot allocate memory

Hi,
while copying some data with sysutils/zrep between computers on the same 
LAN I have received theis error:

16:09:32    382G   pool2tb/misc/virtualbox at 2016-05-10_07.59.00--14d
16:09:33    383G   pool2tb/misc/virtualbox at 2016-05-10_07.59.00--14d
*Fssh_packet_write_poll: Connection to 192.168.0.5 port 22: Cannot 
allocate memory*
WARNING: Removing all zrep configs and snapshots from pool2tb/misc
  (for TAG=zrep)
Continuing in 10 seconds
Destroying any zrep-related snapshots from pool2tb/misc
Removing zrep-related properties from pool2tb/misc
Error: Error transferring pool2tb/misc at zrep_000000 to 
clover-nas3:pool2tb/misc. Resetting

The zrep command is:
# zrep init pool2tb/misc clover-nas3 pool2tb/misc
and the script issues the command:

"zfs send -v -R pool2tb/misc at zrep_000000  | ssh clover-nas3 zfs recv -F 
pool2tb/misc"

The error is reproducible or, at least, I have obtained it with 3 
consequential transfers.
The server is running:
# uname -a
FreeBSD clover-nas2 10.3-RELEASE-p2 FreeBSD 10.3-RELEASE-p2 #0: Wed May  
4 06:03:51 UTC 2016 
root at amd64-builder.daemonology.net:/usr/obj/usr/src/sys/GENERIC amd64

Any idea ?
Thanks
--
Maurizio