Join/leave plugin?

I tried to find a player join/leave message plugin, 1 of them "RustNotifications" is not working, the other 2 I found "Notifier" and "Join Quit Msg" I couldn't get to it with the message: "You do not have permission to view this page or perform this action."
It's weird that I was able to access and downloaded Notifier just 2 day ago, then I tried to look for that plugin again(because it didn't work), I couldn't find it on the list anymore. So I searched on google, with the link to "Notifier" leading me to the oxide page with a message "You do not have permission to view this page or perform this action."
Is it possible that the developers of those plugins has blocked public uses?
How can I get the permission to check those permission-needed mods?
I really need a join/leave mod