Hi There,
Do you happen to run the backdoor on a VM? Dystopia by default has a Sandbox evasion enabled which will scan the environment where the backdoor is running and determine if it is a VM or a sandbox. If that is the case the backdoor is terminated.
Also after running the backdoor, make sure you click a bunch of times as this is also checked by the sandbox evasion to ensure that this is a real person running the backdoor.