Among the various ways to charge a car, a wallbox is one of the best. However, it's always helpful to also have a portable charger to keep in the car in case of emergency or to charge the car during your holiday with your family. Of course, this must always work well to be effective. SomeTesla owners report no problems with charging via a wallbox, but they do have difficulties with the mobile charger, which is unreliable or impossible to use. It's important to clarify that these are two different charging methods, and therefore the car's charging system settings should be checked. Aside from this, you can simply test: use your apparently faulty mobile charger to charge another car and compare its behavior. If it doesn't work after a couple of attempts, then the problem is with the portable Tesla charger itself, which will presumably need to be replaced.