The TRE is not able to establish call ! So it is down, even if there is no alarm on OMC-R.
You could create a QoS Alerter, and you’d see an alarm.
Now, those are the typical actions you could try :
Reset the TRX, the OMU, the TCU, the BTS, etc.
Delete the BTS and re-create it
Same with Abis.