I have idirect modem working fine but suddenly show below meesage TXCAL: error in freq parameter for call_band. setting to max attenuation"", the Rx lock but Tx no, what could be the issue ?

Have you spoken to the network hub about this ? It is possible that they have moved your return link to new frequncy and not told your router. That might explain "error in freq parameter"  I don't know what "call_band" means ?

The change to "max attenuation" suggests that your router has reduced the transmit power to minimum to avoid interference to other people, perhaps by transmitting on the wrong frequency.

Tell us what the NOC has to say.

Other comments please from anyone with iDirect experience.

Thank you I will check with provider