What is the effect of an iRule error such as referencing an undefined variable?

A BIG-IP Operator has made a grave error and deleted a few virtual servers on the active LTM device fronting the web browsing proxies. The BIG-IP Operator has NOT yet performed a configuration sync.
Which command should the LTM Specialist execute on the active LTM device to force a failover to the standby node and restore web browsing?

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An LTM Specialist uses the information in the logs to determine the cause of a failover event in a high-availability (HA) pair.
What caused the failover?

An LTM Specialist defines a receive string in the HTTP monitor and then assigns it to the HTTP pool. The monitor has an interval of 5 seconds and a timeout of 16 seconds.
If the receive string is NOT seen in the the HTTP payload after 20 seconds, how does the LTM device mark the monitor status?

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Refer to the exhibit.
Which URL should be reported to the server/application team as getting user-visible errors?