Bharat Sanchar Nigam [BSNL] — Cannot connect to Kattanam Exchange (Kerala code 0479) from Airtel or Jio mobile phones

For the past 2 months, cannot connect to Kattanam, Kerala exchange (0479) landline number from Jio or Airtel numbers. It always says, "All lines of this route are currently busy, please try later". BSNL Kattanam exchange has major issues keeping up with technology and service. I am trying to call Kattanam landline number [protected] from Jio mobile phone and Airtel Landline. Cannot connect at anytime for the past 2 months. BSNL needs to take a look.