NFS conflicts SSH

[oldandnotmint]

Hi,

I have a desktop-machine running LM20, Mate;
i have a laptop running LM19.3, Mate.
Both are in a home network (mostly wired, other linux machines, router offering DHCP, modem).
I used to be able to connect to above desktop from my laptop, using SSH.
Very recently I installed/setup NFS on the desktop machine.
At the end of setup there, a message showed up saying 'enabling NFS could interfere with SSH' (or something alike).
As I got on with NFS setup on that desktop, I can no longer SSH from laptop to desktop now....
So the word 'could' can be changed in 'will'...
When I try 'ssh <internal ip number of the desktop> on my laptop, the SSH is timed oud without connection (or messages).

Question now: how can I re-enable SSH again?

Thank you.