New MIB for existing device

i am stuck to add new MIB oid it existing device

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Component Version
LibreNMS 1.65-36-g0e96589
DB Schema 2020_06_23_00522_alter_availability_perc_column (170)
PHP 7.3.20
Python 3.6.8
MySQL 5.5.65-MariaDB
RRDTool 1.4.8
SNMP NET-SNMP 5.7.2

this is the error

when doing
[[email protected] discovery]# snmpwalk -v 2c -c [email protected]@2020 -O e 172.19.0.72 1.3.6.1.4.1.2011.6.8.1.7.3
SNMPv2-SMI::enterprises.2011.6.8.1.7.3.0 = INTEGER: 19971
please help me