Do not use your mixer arm in a pan on the hob or to chop nuts (almonds, hazelnuts, etc.), raw meat*, or ice cubes* and do not run it in an empty container. * for models with click and mix accessories, these types of use are possible (see instructions for your mixer arm).
It is extremely important to use the specific Mayonnaise accessories supplied with your appliance (mayonnaise blender + jug) and to respect the quantities of ingredients, particularly the mustard. If you don’t use mustard, you have to compensate with eggs (ie 2 eggs instead of 1 usually). As for the oil quantity, this has to be between min and max. Add the oil really slowly and stir continuously. All the ingredients need to be at room temperature so that the mayonnaise does not curdle.