Common issues when connecting to Slack

Having trouble connecting to Slack? Below are some steps you can take before reaching out for support.


Clear your cache and/or local storage

If you're using Slack for desktop, click Help in the menu bar of your computer, then click Clear Cache and Restart.

If you're on a mobile Slack app, access your Settings, then tap Advanced.


Test Slack in a browser

If you’re using a Slack desktop app for Mac or Windows, you can test your connection to Slack by visiting your workspace from a browser instead. If you’re still unable to connect, continue with the troubleshooting steps below. 


Check your browser settings 

Slack supports the current versions of Chrome, Firefox, Safari, Internet Explorer, and Edge. Read about our support for browsers and operating systems for more.

  • Try connecting to Slack in a different browser.

If you've tried one of the browsers listed above and can't connect, it may be a problem specific to that browser. Try connecting in another supported browser.

  • Open Slack in a private browser window. 

If you’re only able to connect to Slack in a private window, check your computer for conflicting software (more on this below).

  • Turn off browser plugins or extensions.

Try disabling them one at a time to find out if which of these could be causing an issue with Slack.

Note: To use Slack Calls on the web, you'll want to make sure you're using a Google Chrome browser.


Look for conflicting software

  • Scan your computer for spyware or adware.

Malicious software can intercept outgoing traffic and cause issues with connecting to Slack.

  • Temporarily turn off any antivirus or ad-blocking software.

 This may include applications such as McAfee, Norton, or AdBlock Plus. If you’re then able to connect to Slack, one of these applications is causing an issue. Update the software settings to allow *

Certain software can sometimes interfere with Slack connections:

  • Avast
  • AVG
  • Avira Browser Safety
  • Browser Guard
  • Pokki
  • Smart Panel
  • Spyware and adware
  • Visual Discovery by Superfish



Test your connection

Visit to run a simple test that will check your connection to Slack.

Successful tests will display in green, failures or errors in yellow. Here's what the results may indicate:

  • Failing WebSockets

Software or firewall settings may be interfering with your connection to Slack. See details in the next section.

  • Low bandwidth

If your bandwidth results are in kbps (rather than mbps), the problem is due to a slow internet connection.

  • Failing jQuery or CDN

There may be a problem connecting to Fastly, Slack's content delivery network (CDN). Please file a support request.

  • Server connection error

If does not load, please check that your network is set to allow outbound TCP connections to port 443. If loads but you still see an error, please file a support request.


Adjust your proxy or firewall settings

Proxies and firewalls can sometimes interfere with your connection to Slack. If you need help configuring your firewall or proxy, contact your network administrator or an IT professional.

Slack uses WebSockets, a persistent connection between your browser or app and our messaging server, over port 443. Your firewall, as well as any proxies, must be configured to keep these connections open. If you’re running into connectivity issues, here are a few steps that often resolve the problem:

  • Whitelist (in other words, allow) the following sites: * * * * * * *

Note: As our servers as reassigned dynamically within our hosting environment, we don't have a list of static IP addresses to share.

      • Check if your proxy is running SSL decryption. If it is, the proxy must either support WebSockets, or you’ll need to exempt * from SSL decryption.
        • If you’re running Slack on a Mac, head to your computer’s System Preferences, then Network, Advanced, and under Proxies, ensure that Auto Proxy Discovery is disabled.

If you did not configure your network security, this might sound a bit confusing: please contact your trusted IT professional for additional assistance.


Troubleshoot for call connectivity in Slack

Speaking of firewalls, they’re often the reason for most call connection issues. If Slack is having trouble establishing a connection or connecting to the server, read up on troubleshooting for connection errors while making calls in Slack.


Troubleshoot mobile connection issues

Trouble on the go? Check the articles below for help with the mobile device you use.

Still nothing? You can run a connectivity test from your device. After making sure you’re connected to the network that’s giving you problems, visit in your default browser. Then follow the steps outlined above to determine the issue or file a support request.


Contact Slack support

If you've followed the steps above and are still unable to connect to Slack, please reach out to our helpful support team, available 24/7.

You can start by filling out a support request form that mentions issues with connection/connectivity in the subject line. To help us help you, consider including the following details:

  • Copy and paste your results from
  • Describe the action you’re trying to perform, and what’s going wrong.
  • Tell us about the troubleshooting steps you’ve tried.
  • Add screenshots of error messages or other helpful displays.

With that information, we’ll do all we can to help!

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