Slack Calls Not Working — What Causes It & How to Fix It

What Does This Error Mean?

Slack audio or video calls won't start, won't connect, or others can't hear or see you. This is usually a microphone or camera permission that Slack hasn't been granted. Granting permissions in your system settings fixes it in most cases.

Affected Models

Slack on Windows
Slack on Mac
Slack on Chrome browser
Slack on iPhone
Slack on Android

Common Causes

Slack has not been granted microphone or camera permission
Browser is blocking media device access
Wrong audio input or output device is selected in Slack
Weak or unstable internet connection
Slack Calls feature not enabled by the workspace admin

How to Fix It

Allow microphone and camera access for Slack in your system privacy settings.

On Mac: System Settings > Privacy & Security > Microphone/Camera. On Windows: Settings > Privacy > Microphone.
In browser Slack, click the padlock icon in the address bar and allow microphone and camera.

Browsers block media access by default — you must explicitly grant it per site.
In Slack, go to Preferences > Audio & Video and select the correct speaker and microphone.

If you recently added headphones or a new microphone, Slack may still be using the old device.
Test your connection — Slack Calls need a stable connection with low latency.

Move closer to your router or try wired ethernet if calls keep dropping.
Ask your workspace admin to confirm that Slack Calls is enabled for your workspace.

On some plans and configurations, admins can restrict or disable the Calls feature.

When to Call a Professional

This is a permissions or settings issue. No technician is needed — your IT department can help if Calls are disabled at the workspace level.

Frequently Asked Questions

Does Slack Calls require special software to be installed?

No — Slack Calls are built into the Slack desktop and mobile apps. No plugins or extra downloads are needed. Browser-based Slack calls work too, but microphone permission must be manually granted.

Why can others hear me but I can't hear them?

This is almost always the wrong output (speaker) device selected in Slack. Go to Preferences > Audio & Video and change the Speaker setting. Check that your volume is not muted in your system sound settings too.

Can I use Slack calls on the free plan?

Yes — Slack's free plan includes one-to-one calls. Group calls (more than two people) require a paid Slack plan. Check your workspace plan at slack.com/pricing if you're unsure.