EEM offers the ability to monitor events and take informational or corrective action when the
monitored events occur or reach a threshold. An EEM policy is an entity that defines an event and
the actions to be taken when that event occurs. There are two types of EEM policies: an applet or
a script. An applet is a simple form of policy that is defined within the CLI configuration.
To specify the event criteria for an Embedded Event Manager (EEM) applet that is run by sampling
Simple Network Management Protocol (SNMP) object identifier values, use the event snmp
command in applet configuration mode.
event snmp oid oid-value get-type {exact | next} entry-op operator entry-val entryvalue
[exit-comb {or | and}] [exit-op operator] [exit-val exit-value] [exit-time exit-timevalue]
poll-interval poll-int-value
+ oid: Specifies the SNMP object identifier (object ID)
+ get-type: Specifies the type of SNMP get operation to be applied to the object ID specified by
the oid-value argument.
- next - Retrieves the object ID that is the alphanumeric successor to the object ID specified by
the oid-value argument.
+ entry-op: Compares the contents of the current object ID with the entry value using the
specified operator. If there is a match, an event is triggered and event monitoring is disabled
until the exit criteria are met.
+ entry-val: Specifies the value with which the contents of the current object ID are compared to
decide if an SNMP event should be raised.
+ exit-op: Compares the contents of the current object ID with the exit value using the specified
operator. If there is a match, an event is triggered and event monitoring is reenabled.
+ poll-interval: Specifies the time interval between consecutive polls (in seconds)

Explanation
From the output exhibit, we notice that the key-string of R1 is Cisco123! (letter C is in capital) while that of R2 is cisco123!. This causes a mismatch in the authentication so we have to fix their key-strings.
key-string [encryption-type] text-string: Configures the text string for the key. The text-string argument is alphanumeric, case-sensitive, and supports special characters.