Why is my meringue breaking down?

First of all one has to work with a very well de-greased bowl. Do not dry the bowl after washing, but drain it upside down. It is important that the protein is whipped in one go. The fine granulated sugar is added in three times: one part at the start, one part halfway through the beating and the rest just before the end. Reason: the sugar must adhere nicely around the egg white so that the moisture of the egg white cannot be released. Optionally, the egg whites can be heated very lightly during whipping, so that the sugar melts a little and is nicely fixed around the protein cells.