App hang when making a call

[burriedu2]

Description

When making a call the app will sit on the calling screen and will not get to the ringing state. This happens intermittently and we have not been able to consistently reproduce it, but we have been able to observe it happening in our production monitoring

Logs

App Hanging: App hanging for at least 2000 ms.
  libsystem_kernel    0x23f7dbcd4  mach_msg2_trap
  libsystem_kernel    0x23f7df2f4  mach_msg2_internal
  libsystem_kernel    0x23f7df210  mach_msg_overwrite
  libsystem_kernel    0x23f7df058  mach_msg
  libdispatch         0x1ce30fe80  _dispatch_mach_send_and_wait_for_reply
  libdispatch         0x1ce310220  dispatch_mach_send_with_result_and_wait_for_reply
  libxpc              0x1aa024e00  xpc_connection_send_message_with_reply_sync
  Foundation          0x1935349ec  __NSXPCCONNECTION_IS_WAITING_FOR_A_SYNCHRONOUS_REPLY__
  Foundation          0x193f7d1b0  -[NSXPCConnection _sendInvocation:orArguments:count:methodSignature:selector:withProxy:]
  CoreFoundation      0x195edb1c8  ___forwarding___
  CoreFoundation      0x195ee31fc  __forwarding_prep_0___
  AudioSession        0x1bf65f734  avas::client::GetPropertyXPC
  AudioSession        0x1bf65f538  avas::client::SessionCore::GetProperty
  AudioSession        0x1bf668ca8  avas::client::SessionCore::GetProperty_DefaultToZero<T>
  AudioSession        0x1bf668794  avas::client::SessionCoreLegacy_iOS::ioBufferDuration
  AudioSession        0x1bf66cc48  avas::client::KVOProperty<T>::UpdateIfDirty
  AudioSession        0x1bf66c900  avas::client::KVOProperty<T>::UpdateIfDirty
  AudioSession        0x1bf67f1f4  -[AVAudioSession IOBufferDuration]
  TwilioVoice         0x102c2f9b8  -[TVORTCAudioSession IOBufferDuration]
  TwilioVoice         0x102c33f04  +[TVORTCAudioSessionConfiguration currentConfiguration]
  TwilioVoice         0x102b3a5c4  -[TVODefaultAudioDevice updateChannelConfiguration] (TVODefaultAudioDevice.mm:178)
  TwilioVoice         0x102b3a06c  __34-[TVODefaultAudioDevice setBlock:]_block_invoke (TVODefaultAudioDevice.mm:97)
  TwilioVoice         0x102b20018  +[TwilioVoiceSDK connectWithOptions:delegate:] (TwilioVoice.mm:238)
  xxxxxxxxxxx       0x100bfeedc  -[TwilioVoiceReactNative(CallKit) performVoiceCallWithUUID:client:completion:]
  xxxxxxxxxxx       0x100bffac4  -[TwilioVoiceReactNative(CallKit) provider:performStartCallAction:]
  CallKit             0x1c75eaa60  -[CXProvider performAction:]
  CallKit             0x1c75b6af0  __49-[CXAbstractProvider provider:commitTransaction:]_block_invoke.7
  libdispatch         0x1ce2f4ad8  _dispatch_call_block_and_release
  libdispatch         0x1ce30e7e8  _dispatch_client_callout
  libdispatch         0x1ce32bb20  _dispatch_main_queue_drain.cold.5
  libdispatch         0x1ce303ec4  _dispatch_main_queue_drain
  libdispatch         0x1ce303e00  _dispatch_main_queue_callback_4CF
  CoreFoundation      0x195f002c4  __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__
  CoreFoundation      0x195eb3b38  __CFRunLoopRun
  CoreFoundation      0x195eb2a68  _CFRunLoopRunSpecificWithOptions
  GraphicsServices    0x236ac0494  GSEventRunModal
  UIKitCore           0x19b876ba0  -[UIApplication _run]
  UIKitCore           0x19b81fa74  UIApplicationMain
  xxxxxxxxxxx       0x1000198f0  main
  0x192ecae28  <redacted>

  libsystem_kernel    0x23f7dbcd4  mach_msg2_trap
  libsystem_kernel    0x23f7df2f4  mach_msg2_internal
  libsystem_kernel    0x23f7df210  mach_msg_overwrite
  libsystem_kernel    0x23f7df058  mach_msg
  libdispatch         0x1ce30fe80  _dispatch_mach_send_and_wait_for_reply
  libdispatch         0x1ce310220  dispatch_mach_send_with_result_and_wait_for_reply
  libxpc              0x1aa024e00  xpc_connection_send_message_with_reply_sync
  Foundation          0x1935349ec  __NSXPCCONNECTION_IS_WAITING_FOR_A_SYNCHRONOUS_REPLY__
  Foundation          0x193f7d1b0  -[NSXPCConnection _sendInvocation:orArguments:count:methodSignature:selector:withProxy:]
  CoreFoundation      0x195edb1c8  ___forwarding___
  CoreFoundation      0x195ee31fc  __forwarding_prep_0___
  AudioSession        0x1bf65f734  avas::client::GetPropertyXPC
  AudioSession        0x1bf65f538  avas::client::SessionCore::GetProperty
  AudioSession        0x1bf668ca8  avas::client::SessionCore::GetProperty_DefaultToZero<T>
  AudioSession        0x1bf668794  avas::client::SessionCoreLegacy_iOS::ioBufferDuration
  AudioSession        0x1bf66cc48  avas::client::KVOProperty<T>::UpdateIfDirty
  AudioSession        0x1bf66c900  avas::client::KVOProperty<T>::UpdateIfDirty
  AudioSession        0x1bf67f1f4  -[AVAudioSession IOBufferDuration]
  TwilioVoice         0x102c2f9b8  -[TVORTCAudioSession IOBufferDuration]
  TwilioVoice         0x102c33f04  +[TVORTCAudioSessionConfiguration currentConfiguration]
  TwilioVoice         0x102b3a5c4  -[TVODefaultAudioDevice updateChannelConfiguration] (TVODefaultAudioDevice.mm:178)
  TwilioVoice         0x102b3a06c  __34-[TVODefaultAudioDevice setBlock:]_block_invoke (TVODefaultAudioDevice.mm:97)
  TwilioVoice         0x102b20018  +[TwilioVoiceSDK connectWithOptions:delegate:] (TwilioVoice.mm:238)
  xxxxxxxxxxx       0x100bfeedc  -[TwilioVoiceReactNative(CallKit) performVoiceCallWithUUID:client:completion:]
  xxxxxxxxxxx       0x100bffac4  -[TwilioVoiceReactNative(CallKit) provider:performStartCallAction:]
  CallKit             0x1c75eaa60  -[CXProvider performAction:]
  CallKit             0x1c75b6af0  __49-[CXAbstractProvider provider:commitTransaction:]_block_invoke.7
  libdispatch         0x1ce2f4ad8  _dispatch_call_block_and_release
  libdispatch         0x1ce30e7e8  _dispatch_client_callout
  libdispatch         0x1ce32bb20  _dispatch_main_queue_drain.cold.5
  libdispatch         0x1ce303ec4  _dispatch_main_queue_drain
  libdispatch         0x1ce303e00  _dispatch_main_queue_callback_4CF
  CoreFoundation      0x195f002c4  __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__
  CoreFoundation      0x195eb3b38  __CFRunLoopRun
  CoreFoundation      0x195eb2a68  _CFRunLoopRunSpecificWithOptions
  GraphicsServices    0x236ac0494  GSEventRunModal
  UIKitCore           0x19b876ba0  -[UIApplication _run]
  UIKitCore           0x19b81fa74  UIApplicationMain
  xxxxxxxxxx       0x1000198f0  main
  0x192ecae28  <redacted>

Versions

All relevant version information for the issue.

Voice iOS SDK

TwilioVoice (6.12.1) via CocoaPods and React Native

Xcode

16.2.0

iOS Version

OS Version: iOS 26.1
Build
23B85
Kernel Version
Darwin Kernel Version 25.1.0: Thu Oct 23 11:09:52 PDT 2025; root:xnu-12377.42.6~55/RELEASE_ARM64_T8101

iOS Device

iPhone 12 (D53gAP)

[bobiechen-twilio]

@burriedu2

Thanks for reaching out. While we investigate the issue, here are a few questions:

• Have you ever been able to reproduce the hang in the dev environment? and if yes, did the app/call continue to work after 2-3 seconds or did it result in a total unresponsiveness and can only be resolved by terminating the application?
• When you said "will not get to the ringing state", did you mean the app and the call are still working (not blocking the UX on the main thread) but just would not transition to the next call state (connected/disconnected/failed)?
• Are you able to reproduce the same issue with any of the example apps? (Voice iOS quickstart / Voice React Native example app)

[burriedu2]

@bobiechen-twilio

Thank you for your quick response.

1. We have not been able to reproduce this in our dev environment. When we have observed this happening it is usually after a long period of using the app (1+ hour)
2. The app does not block the main UI thread and they are able to exit the call and continue to use the app. The call usually goes to ringing and then connected status, but it appeared to just sit on the call and never get to the ringing status
3. I will see if we can come up with a minimal app reproduction of the issue

[bobiechen-twilio]

Hi @burriedu2

Sorry that we have been slow in responding back these days.
Thanks for the updates. Just to clarify, the "hang" is actually about call state transition instead of the (short/substantially long) non-responsiveness, right?
If it's possible, are you able to collect Twilio Call SIDs from these affected users, so we can analyze from Twilio's perspective to see whether the state transition is a Programmable Voice issue or and SDK issue?