Cant connect to TVHeadend from Kodi

Hi Guys,

I have a TvHeadend server running on a Synology NAS and I am trying to get a TvHeadend client to connect on an install of OpenELEC 7 with Kodi Jarvis 16.1.
I know the server is OK as I have another install of Kodi 16.1 on a Amazon FireStick which connects OK.
The only difference between the two installs is that the firestick is running client version 2.2.15 and the one I cant get to work on the OpenELEC is 2.2.20.
I thought it might be that I had them set up with the same user name and password to connect to TvHeadend so i created another user but that didnt work.
im not sure what the entries in the kodi.log is telling me:

00:43:50 T:2656195488 ERROR: AddOnLog: Tvheadend HTSP Client: pvr.hts – failed to write (Invalid argument)
00:43:50 T:2656195488 ERROR: AddOnLog: Tvheadend HTSP Client: pvr.hts – failed to transmit
00:43:50 T:2656195488 ERROR: AddOnLog: Tvheadend HTSP Client: pvr.hts – failed to send hello
00:43:51 T:2681238432 ERROR: ADDON: Dll Tvheadend HTSP Client – Client returned bad status (1) from Create and is not usable
00:43:51 T:2681238432 WARNING: UpdateAndInitialiseClients – failed to create add-on Tvheadend HTSP Client, status = 1

Do you guys have any thoughts as to what i can try next?

thanks for any help,

Degs