Known issues

This article provides information about limitations and known issues related to the Azure Communication Services Calling SDKs and Azure Communication Services Call Automation APIs


There are multiple factors that can affect the quality of your calling experience. Refer to the network requirements documentation to learn more about Communication Services network configuration and testing best practices.

Azure Communication Services Calling SDKs

JavaScript SDK

This section provides information about known issues associated with the Azure Communication Services JavaScript voice and video calling SDKs.

Refreshing a page doesn't immediately remove the user from their call

If a user is in a call and decides to refresh the page, the Communication Services media service won't remove this user immediately from the call. It will wait for the user to rejoin. The user will be removed from the call after the media service times out.

It's best to build user experiences that don't require end users to refresh the page of your application while in a call. If a user refreshes the page, reuse the same Communication Services user ID after they return back to the application.

From the perspective of other participants in the call, the user will remain in the call for a minute or two.

If the user rejoins with the same Communication Services user ID, they'll be represented as the same, existing object in the remoteParticipants collection.

If the user was sending video before refreshing, the videoStreams collection will keep the previous stream information until the service times out and removes it. In this scenario, the application may decide to observe any new streams added to the collection and render one with the highest id.

It's not possible to render multiple previews from multiple devices on web

This is a known limitation. For more information, see the calling SDK overview.

Enumerating devices isn't possible in Safari when the application runs on iOS or iPadOS

Applications can't enumerate/select mic/speaker devices (like Bluetooth) on Safari iOS/iPad. This is a known operating system limitation.

If you're using Safari on macOS, your app won't be able to enumerate/select speakers through the Communication Services Device Manager. In this scenario, devices must be selected via the OS. If you use Chrome on macOS, the app can enumerate/select devices through the Communication Services Device Manager.

Audio connectivity is lost when receiving SMS messages or calls during an ongoing VoIP call

This problem may occur due to multiple reasons:

  • Some mobile browsers don't maintain connectivity while in the background state. This can lead to a degraded call experience if the VoIP call was interrupted by an event that pushes your application into the background.
  • Sometimes, an SMS or PSTN call captures the audio sound, and doesn't release audio back to the VoIP call. Apple fixed this issue in iOS versions 14.4.1+.

Client library: Calling (JavaScript)
Browsers: Safari, Chrome
Operating System: iOS, Android

Repeatedly switching video devices may cause video streaming to temporarily stop

Switching between video devices may cause your video stream to pause while the stream is acquired from the selected device.

Possible causes

Switching between devices frequently can cause performance degradation. Developers are encouraged to stop one device stream before starting another.

Bluetooth headset microphone is not detected therefore is not audible during the call on Safari on iOS

Bluetooth headsets aren't supported by Safari on iOS. Your Bluetooth device won't be listed in available microphone options and other participants won't be able to hear you if you try using Bluetooth over Safari.

Possible causes

This is a known macOS/iOS/iPadOS operating system limitation.

With Safari on macOS and iOS/iPadOS, it is not possible to enumerating/selecting speaker devices through the Communication Services Device Manager since speakers enumeration/selection is not supported by Safari. In this scenario, your device selection should be updated via the operating system.

Rotation of a device can create poor video quality

Users may experience degraded video quality when devices are rotated.

Devices affected: Google Pixel 5, Google Pixel 3a, Apple iPad 8, and Apple iPad X
Client library: Calling (JavaScript)
Browsers: Safari, Chrome
Operating System: iOS, Android

Camera switching makes the screen freeze

When a Communication Services user joins a call using the JavaScript calling SDK and then hits the camera switch button, the UI may become unresponsive until the application is refreshed or browser is pushed to the background by user.

Devices affected: Google Pixel 4a
Client library: Calling (JavaScript)
Browsers: Chrome
Operating System: iOS, Android

Possible causes

Under investigation.

If the video signal was stopped while the call is in "connecting" state, the video will not be sent after the call started

If users decide to quickly turn video on/off while call is in Connecting state - this may lead to problem with stream acquired for the call. We encourage developers to build their apps in a way that doesn't require video to be turned on/off while call is in Connecting state. This issue may cause degraded video performance in the following scenarios:

  • If the user starts with audio and then start and stop video while the call is in Connecting state.
  • If the user starts with audio and then start and stop video while the call is in Lobby state.
Possible causes

Under investigation.

Enumerating/accessing devices for Safari on MacOS and iOS

If access to devices are granted, after some time, device permissions are reset. Safari on MacOS and on iOS does not keep permissions for very long time unless there is a stream acquired. The simplest way to work around this is to call DeviceManager.askDevicePermission() API before calling the device manager's device enumeration APIs (DeviceManager.getCameras(), DeviceManager.getSpeakers(), and DeviceManager.getMicrophones()). If the permissions are there, then user will not see anything, if not, it will re-prompt.

Devices affected: iPhone
Client library: Calling (JavaScript)
Browsers: Safari
Operating System: iOS

Sometimes it takes a long time to render remote participant videos

During an ongoing group call, User A sends video and then User B joins the call. Sometimes, User B doesn't see video from User A, or User A's video begins rendering after a long delay. This issue could be caused by a network environment that requires further configuration. Refer to the network requirements documentation for network configuration guidance.

Using 3rd party libraries to access GUM during the call may result in audio loss

Using getUserMedia separately inside the application will result in losing audio stream since a third party library takes over device access from ACS library. Developers are encouraged to do the following:

  1. Don't use 3rd party libraries that are using internally GetUserMedia API during the call.
  2. If you still need to use 3rd party library, only way to recover is to either change the selected device (if the user has more than one) or restart the call.

Browsers: Safari
Operating System: iOS

Possible causes

In some browsers (Safari for example), acquiring your own stream from the same device will have a side-effect of running into race conditions. Acquiring streams from other devices may lead the user into insufficient USB/IO bandwidth, and sourceUnavailableError rate will skyrocket.

Azure Communication Services Call Automation APIs

Following are the known issues in the Azure Communication Services Call Automation APIs

  • The only authentication supported at this time for server applications is using a connection string.

  • Calls should be make only between entities of the same Azure Communication Service resource. Cross resource communication is blocked.

  • Calls between Teams' tenant users and Azure Communication Service user or server application entities are not allowed.

  • If an application dials out to two or more PSTN identities and then quits the call, the call between the other PSTN entities would be dropped.