Regarding to ARI Rest API's

Hi I am Using node-ari client package using typescript and i am doing load testing of my application but the issue i am facing is i am testing this on 2000 channels like a outbound calls but then LEG B channel hangup i am manually hanging up the LEG A channel using ari.channels.hangup and i am using callback here not await but like in 1000 LegA channel
sometime 40 Channels are left, sometimes 20 and so on
I also debug the senario and found out that i hit the hangup but the channel is not hangup and i did’nt receive any response from that when i tried to hangup that channel after load test it will hangup smoothly

console.log("ABOUT TO HANGUP")
 ari.channels.hangup({channelId}).then(async (channel) => { 
console.log(channel, "Hello");

and i have recieved "HELLO "in this but the channels which are stuck the code never went inside but log the outer console,
Please help me is there any thing i am missing?