Drops signal

[W9JFA]

Hello All:
Have a Zumspot with Pi-Star. Unit had been operating properly. I tried to rename it but used a wrong character in the name and was unable to open Pi-Star dashboard as it would not recognize the login name.
To solve this I formatted the card and reloaded the Pi-Star software. I can now open the dashboard and find the unit. I can also configure it and change the settings. I am only using it for DSTAR and P25. I can connect to a reflector or chat room, but when someone transmits the unit keys the radio for about 2 seconds then drops the audio. It stays connected to the reflector and the next time someone transmits it will again key the radio, but again drops the signal after a second or two. Any suggestions what might be causing this and what I might do to correct it?
I have reformatted and installed the software several times with the same results.
Thanks
John A.
W9JFA