Twilio client voice call speaker ON/OFF issue

Question

I am using Twilio client voice call service for calling.

Here I am facing issue in spearke ON/OFF feature.I am able to Mute/Unmute call but not able to turn On/OFF speaker. I have a same instance for both functionality. I have also checked their demo project basic phone in that this speaker ON/OFF is working and I am doing same thing in my project bur not able to do the same.

Here is my code:

if(isSpeaker == NO)
{
     isSpeaker=YES;
     [self.phone setSpeakerEnabled:YES];
}
else{
     isSpeaker=NO;
     [self.phone setSpeakerEnabled:NO];
}
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