I am developing a custom block plugin and I have created the all neccessary files in it. But when I am installing it from admin end it's refer to me the page /admin/tool/installaddon/index.php. and getting error like "The plugin ZIP package must contain just one directory, named to match the plugin name. The file provided is not a valid plugin ZIP package"
I have try many time but getting the same error and anyone help me and guide me why this error coming.