My Delonghi Magnifica ESAM 4200.s makes coffee and then cuts out. Any suggestions as to why?

If you have observed the problem on different outlets and even in different houses, the only common factor is the machine itself. The exact cause can’t be assessed via the Internet and unless you are experienced with repairing electrical machinery, I would strongly discourage you to start experimenting blindly. The missing error lights are not an indicator here, they would only signal a problem that an otherwise functional machine can detect via the built-in self-checks. Tripping a circuit breaker is in a different league of defect.

For your own safety: Please stop using the machine (faulty electric alone is bad enough, add water to the mix and it gets really dangerous), even if it seems to “work”, sort of. Contact a qualified service technician or the seller/manufacturer (especially if it’s still under warranty) and have them assess the situation.