Due to limitations in metric names, topics with a period ('.') or underscore ('_') could collide. To

Due to limitations in metric names, topics with a period (’.’) or underscore (’_’) could collide. To avoid issues it is best to use either, but not both. Created topic “topic_start”.

把下划线换成别的就可以！其实不用管这个，他也是可以创建成功的！