Troubleshoot audio and video issues in Slack

Having trouble with audio or video in huddles or calls? Read on to learn how to troubleshoot common issues with connections, audio, video, and screen sharing. 

Note: Slack calls will not be available after March 29, 2023. During the transition to huddles, support for troubleshooting calls issues will be limited.


Run a test to identify issues

Our audio, video and screen sharing test can help identify problems you may be having while on a huddle or call. After running the test, use the troubleshooting information in this article to address any issues flagged in your results. Here's how to run the test:

  1. From your desktop, click your profile picture in the top right.
  2. Select Preferences from the menu.
  3. Click Audio & video in the left-side column.
  4. Below Troubleshooting, click Run an audio, video and screensharing test. The test will open in a new window. 
  5. Check that your preferred speaker, microphone and camera devices appear in the drop-down menus, then click Start test.

Note: The audio, video and screen sharing test is only available from the Slack desktop app and Slack in Chrome.


Bandwidth issues

Bandwidth requirements

Your experience with huddles and calls depends on the strength of your network connection and your bandwidth: 

Type of huddle or call Download speed Upload speed
Voice huddle or call 200 kbps 100 kbps
Video huddle or call* (2 participants) 600 kbps 600 kbps
Video huddle or call* (3 participants) 1.2 Mbps 600 kbps
Video huddle or call* (5+ participants) 2 Mbps 600 kbps

*Requirements are the same when screen sharing


Troubleshooting

If your bandwidth meets or exceeds our requirements and you're experiencing issues with huddle or call quality, audio cutting in and out, or lag, try one of these options: 

  • Run a speed test to double-check that your device's bandwidth meets our requirements. 
  • Switch to a wired connection if possible, or move closer to your Wi-Fi router. 
  • Reset your router by turning it off and back on again.  


Connection issues

Resolve connection issues

If Slack is unable to establish a huddle or call connection, try these options to narrow down the source of the connection issues: 

  1. Make sure you're on the latest version of the Slack desktop or mobile app. If not, update your app
  2. If you're having trouble with huddles or calls on the desktop app, open your workspace in Google Chrome and try starting a huddle or making a call. 
  3. If you can't connect from the desktop app or browser, try starting a huddle or call from the Slack mobile app on the same Wi-Fi network. If you can connect, there may be an issue with your computer, like an anti-virus software blocking the connection. If you can start huddles or make calls from your mobile device with data but not Wi-Fi, that most likely indicates an issue with your network. 

Tip: If you can't connect to Slack at all, visit Troubleshoot connection issues for help.

Update firewall settings

Huddles or calls connection problems may also be caused by an issue with your firewall. If you're experiencing connection errors, you (or someone from your company's IT team) may need to adjust your outbound connection settings: 

  • Check that your network is set up to allow outbound traffic to UDP/22466. Otherwise, huddles and calls will use TCP/443 for media transport (video and audio).
  • Allow outbound traffic to TCP/443. This is required for huddles and calls to function, even if outbound traffic to UDP/22466 is allowed for media transport.
  • If you’d like, you can limit access to a specific IP range: 99.77.128.0/18.

If your environment requires you to allow Slack's required domains, make sure you approve *m.chime.aws. We aren't able to provide a list of static domains, and suggest allowing by wildcard to avoid any network disruptions.


Audio issues

If you experience audio issues during a huddle or call, quit and reopen the Slack desktop app or your browser. If that doesn’t help, try restarting your device.

Check audio input and output sources

If neither of the options above works, go to your audio and video preferences and check the following:

  • Make sure you've selected the correct microphone and speaker.
  • Test your microphone by saying a few words. If the voice meter doesn't move up and down as you speak, try the other options in the microphone dropdown menu.
  • Test your speaker by clicking Test. You'll hear a chime if your speaker is unmuted and working correctly.


Check audio settings

Check to make sure your audio isn't muted, then confirm that Slack has permission to access your microphone: 

Mac

Windows

Chrome

  1. Open System Preferences.
  2. Select Security & Privacy, then click the Privacy tab. 
  3. Select Microphone from the list on the left. 
  4. Check the box next to Slack. If it's already checked, uncheck and recheck it. 
If you're on Windows 10 and others can't hear you on a huddle or call, follow these steps to make sure you've granted Slack access to your microphone:
  1. Open Settings
  2. Select Privacy
  3. Click Microphone
  4. Toggle the setting on to allow apps to access your microphone.
  5. In the list of Microsoft Store apps, find Slack and toggle the setting on.


There's also a known issue with Windows 10 where Slack cannot detect communications devices (like headphones or headsets) that are not the system default. To set your preferred device as the system default, follow the steps below:

  1. Open Settings
  2. Select System
  3. Select Sound
  4. Below Select your output device, choose the one you want from the drop-down menu. 

Lastly, check that your audio drivers are up to date. If they're not, updating may resolve these issues. 

Follow these steps to make sure you've granted Slack microphone access in Chrome:
  1. From Chrome, click the  three dots icon in the top right and select Settings from the menu. 
  2. Select Privacy & security in the left sidebar. 
  3. Click Site settings
  4. Click Microphone
  5. Check that Slack has not been blocked. Add your workspace URL to the Allow list to always allow Slack microphone access. 

Note: If you use a third-party calling app and Slack calls, Slack's access to your microphone may get revoked when switching between the two. You can follow the steps above to re-grant Slack access to your microphone.


Video issues

Having issues with video? Quit and reopen the Slack desktop app or your browser. You can also try restarting your device.

Check camera and video settings

If restarting your device or quitting and reopening Slack doesn't help, try these options: 

  • If you're using the Slack desktop app, check if video calls work from Google Chrome (or vice versa if you're using Chrome).
  • Check your audio and video preferences to make sure the correct camera is selected. You should see yourself in your own video thumbnail.  
  • Check if your camera works with another calling app (like Zoom or Webex). These apps use different technology than huddles and calls in Slack, so if issues persist, that may indicate a hardware issue with your camera. 

Tip: If you're using an external camera, make sure to plug it in to your computer before starting a call. If you plug it in after a call has started, video won't display. 

Check camera permissions

If others can't see you on a video huddle or call, Slack may not have access to your camera. Follow these steps to check your camera permissions: 

Mac

Windows

Chrome

  1. Open System Preferences.
  2. Select Security & Privacy, then click the Privacy tab. 
  3. Click Camera
  4. Check the box next to Slack. If it's already checked, uncheck and recheck it. 
  1. Open Settings
  2. Select Privacy
  3. Click Camera.
  4. Toggle the setting on to allow apps to access your camera.
  5.  In the list of Microsoft Store apps, find Slack and toggle the setting on.

You can also check to make sure your video drivers are up to date. If they're not, updating them may clear up issues. 

  1. From Chrome, click the  three dots icon in the top right and select Settings from the menu. 
  2. Select Privacy & security in the left sidebar. 
  3. Click Site settings
  4. Click Camera
  5. Check that Slack has not been blocked. Then, add your workspace URL to the Allow list to always allow Slack camera access. 

Note: If you notice your computer running slowly during video huddles or calls, that may be due to high Central Processing Unit (CPU) usage. For huddles or calls with many participants, disabling your video or turning off noise suppression may help speed things up.


Screen sharing issues

If you're unable to share your screen, use these steps to troubleshoot: 

Mac

Windows

If you're running macOS version 10.15 and aren't able to share your screen, check your operating system settings:
  1. Open System Preferences
  2. Click Security & Privacy, then select the Privacy tab. 
  3. Select Screen Recording from the list on the left. 
  4. Click the  lock icon to make changes. 
  5. Check the box next to Slack, then click the  lock icon again to save your changes. 
  6. Quit and reopen the Slack desktop app. 
If you're using Windows 10 and have clicked Share screen but the other members of your huddle or call can't see it, try opening your laptop if it's closed. If that doesn't resolve the problem, unplug or undock any external monitors.

Note: It's not possible to share your screen on Linux.


Still having trouble?

Reach out to our Support team and include the following information if you can: 

  • The results from your audio, video and screen sharing test.
  • Timestamps for any recent huddles or calls that you experienced an issue with.
  • Screenshots or a screen recording showing any errors you've seen or the problem you're experiencing.
  • Any other details you remember. For example, it's really helpful for us to know if problems arose immediately after you started a huddle or call, a few minutes into the huddle or call, when you started screen sharing, etc.