Blue/yellow LED means that the openSPOT2 is connected to the Wi-Fi network and trying to connect to the selected server
http://manuals.sharkrf.com/openspot2/en/led-states.html
What you need to do is to use another server which works.
If pressing PTT on your transceiver helps, then it means that your transceiver has a server's name/callsign set as the URCALL (destination callsign), and not CQCQCQ, and this makes the openSPOT2 switch to that server.
What does not work using a C4FM transceiver? Please explain your issue in full detail.