Proble in Digium TE220

Hello, I get this messages every 5 minutes o more frequently:

[Jun 15 11:03:16] WARNING[879]: chan_dahdi.c:4090 handle_alarms: Detected alarm on channel 8: Red Alarm
[Jun 15 11:03:16] WARNING[879]: chan_dahdi.c:1810 dahdi_disable_ec: Unable to disable echo cancellation on channel 8: Invalid argument
[Jun 15 11:03:16] WARNING[879]: chan_dahdi.c:4090 handle_alarms: Detected alarm on channel 9: Red Alarm

And I get hang up in calls. Can anyone help me?