Why I am getting error while doing SNMP walk?

Question

I am doing snmp walk using following php code

<?php
  $session = new SNMP(SNMP::VERSION_1, "10.221.11.123", "community");
  $fulltree = $session->walk(".");
  print_r($fulltree);
  $session->close();
?>

On execution, I am getting following error

PHP Warning: SNMP::walk(): Error in packet at 'SNMPv2-SMI::enterprises.77.1.1.3.0': (genError) A general failure occured in /opt/test/test.php on line 3

Just for more info, the snmpwalk is done to a windows 2022 server machine hosted on ec2. How can I fix this ?