Reasons for the failure of the idea of collective security?

To a greater extent, this idea was put forward by the Soviet Union in the 30s of the 20th century, this was due to the coming to power of radical National Socialists in Germany. However, in the first place, the USSR was not supported and the negotiations were thwarted by Britain and France. Last but not least, the failure of the idea of collective security is associated with the so-called “policy of appeasing the aggressor.” In this case, the same France, England indulge Nazi Germany and its leader Adolf Hitler, which led to the capture of Czechoslovakia, the Anschluss of Austria.