well, found the solution!
double checked my Cisco router, using Wireshark I could see I was connecting - but never getting any responses from the remote unit.
After looking at the Radio Settings in the control unit I saw this:
I double clicked the "SIP contact" IP address:
I noticed that there is a space behind the IP address - so this is a parser issue in the RRC - probably in the remote SIP part -as I could see the control unit try to connect - but I never saw any connections coming back.
When I remove the space behind the IP address - everything goes back to normal.
This has been replicated on the local LAN also (I have two RRC's)
Not being a software bug per se - it's something that can cause issues as IP addresses are often copied and pasted and this space is often copied with them. With proper input parsing this "issue" could be totally avoided.
73, Benni TF3CY