trouble with install.backdoor()

[Celestior]

i use this script, i have no error but the backdoor look to not install ...

/** @param {NS} ns */
export async function main(ns) {

for (let Factionservername of ['run4theh111z', 'CSEC', 'I.I.I.I', 'avmnite-02h']) {
ns.exec('nserv.js', 'home', 1, Factionservername);
ns.singularity.connect(Factionservername)
await ns.singularity.installBackdoor();
ns.tprintf('Successfully installed backdoor on ' + Factionservername)

}
}

[_JJ_]

you cannot directly connect to these servers
its just the like terminal connect you can only connect to server that are neighbours of the current terminal server or those where you have a backdoor installed