Can I permently connect the resistant of a coffee machine
In series with the mains supply, the thermostat and the heating element there is mostprobably also a thermal fuse. It is soldered in place and opens permanently if the temperature of the coffee machine has been to hot. This is done to prevent damage or even fire to your house. If that is the case the fuse must be replaced with one of the same specifications.

A warning again. Dont short circuit the fuse because of the increased risk of fire hazard and be carefull since you are working with a mains supplied appliance.