SNMP Datatype: SNMP_EXCEPTION_NOSUCHINSTANCE while loading 3rd party MIB

Hello,

I am trying to add a new sensor to PRTG to monitor zscaler server.
I have copied the MIB file to PRTG managed server and configured SNMP to load the file.

When i run a SNMP tester in PRTG I get the below error:

----------------------- New Test -----------------------
Paessler SNMP Tester - 20.2.4 Computername: DEVICENAME Interface: (x.x.x.x)
27/05/2021 08:29:09 (2 ms) : Device: x.x.x.x
27/05/2021 08:29:09 (5 ms) : SNMP v2c
27/05/2021 08:29:09 (7 ms) : Custom OID 1.3.6.1.4.1.46262.5.1.0
27/05/2021 08:29:09 (15 ms) : SNMP Datatype: SNMP_EXCEPTION_NOSUCHOBJECT
27/05/2021 08:29:09 (18 ms) : -------
27/05/2021 08:29:09 (20 ms) : Value: #N SNMP_EXCEPTION_NOSUCHOBJECT222
27/05/2021 08:29:09 (22 ms) : Done

I have tried a walk from SNMP Tester and get no response.

----------------------- New Test -----------------------
Paessler SNMP Tester - 20.2.4 Computername: DEVICENAME Interface: (x.x.x.x)
27/05/2021 08:29:48 (2 ms) : Device: x.x.x.x
27/05/2021 08:29:48 (5 ms) : SNMP v2c
27/05/2021 08:29:48 (7 ms) : Walk 1.3.6.1.4.1.46262.5.2

On the SNMP agent server i get the below error:
snmpwalk -v2c -Ir -c arlsnmp x.x.x.x 1.3.6.1.4.1.46262.5.2
ZSCALER-PROCESSHEALTH-MIB::processhealthTable = No Such Object available on this agent at this OID

My Linux Centos 7 server has SNMP v1 and v2c enabled and running. There is no firewall running on the server.
The server are behind proxy.
The servers are being monitored by PRTG but the need to add a new sensor.

I need to know where should i load the MIB file : PRTG SERVER or the Managed Device. And where did i go wrong here?

nosuchobject222 snmp-exception-nosuchobject zscaler