These timeout messages can sometimes be seen when running Jmeter script monitors but what is the difference between them:
Error code 1042: "Timeout of Monitor Sequence"
Error code 7011: "Operation Time Out"
Jmeter is a complex java application and its start time and time needed to cleanup and shutdown depend on the complexity of the testing script, resources allocated and the global system load. Thus, when the Jmeter test is started, there is a small amount of time added on top of the user specified timeout period (approx. 10 seconds). If the script times out then depending at what stage that occurs will determine what error message is shown.
As an example if using the maximum user specified timeout of 90 seconds the total allowed time will be 100 seconds. When the script finishes within the 100 seconds it returns valid output, so even though the script failed (timeout), the user receives a full report and the result is timeout 7011. However if the script is still running after the 100 seconds it is abruptly ended, doesn't provide any information and the result is timeout 1042. The monitor logs should show that all 7011 timeouts ended shortly after the 90 seconds.