Thanks for replies and help with this.
After a bit of research I have found out that I think its an IP address conflict when using a VPN on the client that hosts the channels server. I have had no issues up until last week with using the VPN on the client that hosts the channels server so tried to think what had changed. It turns out my ISP IP address changed last week and then I get an error in the log that the channels dvr server is pointed to the IP address that the VPN had assigned.
If I then disconnect the VPN then reconnect then the channels DVR.net is now pointed at my ISP IP address correctly and I am then having none of the issues I reported before. Its all very confusing but I just need to remember to disconnect and re-connect my VPN if my ISP IP address changes.
I understand the error as channelsdvr.net is pointed at my VPN IP address which wouldn't work but if i then reconnect my VPN channelsdvr.net points at my ISP IP address again.