It is noticed, some time job stuck and keep on spinning for some reason. It’s neither finish nor cancel. Next scheduler can’t trigger as well previous job still running.
Need a solution to cancel jobs and generate alerts.
This is a little hidden: https://documentation.matillion.com/docs/2282963#cancelling-tasks
You can try Ctrl+Right Click --> Cancel Task and Continue option. But sometimes this doesn't work either and requires a server restart.