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I can’t register Sketch but I’m connected to the internet

Although Sketch doesn’t always require you to be connected to the internet it does sometimes need to connect to a network, for example when you register your copy of the app, or when Sketch needs to validate your license.

If Sketch tries to register/validate your license and can’t connect to our server you’ll probably see the following message:

“Could not reach the server to validate your license. Please check your connection and try again.”

To register Sketch, the app needs to be able to connect to the following:


Host Port
api.sketchapp.com 443 (https)

If you’re using a firewall, you will need to change your settings to allow traffic to this host. If you’re using a proxy server, you will need to whitelist our domain, as we don’t allow re-signing of certificates.

Note: Sketch does not currently support all (authenticated) proxy setups.

If you’re still unable to register Sketch after you’ve fixed these settings, then we recommend disabling all plugins and restarting Sketch. Some plugins launch a proxy when you open Sketch and this can sometimes affect our global network settings.

If you’re struggling to register or validate Sketch, we’re here to help. To allow us to better understand what issue you might be experiencing, it’s important that you send us the following information:

Note: These issues are normally caused by local network issues so if you have an IT team or department, they can also analyze the following information to try and determine why you can’t connect to our API server.

Console logs

Console logs can help us identify exactly what’s happening when you try to register Sketch. Follow these instructions to compile and send us the logs.

  • Launch the Console app (found in Applications > Utilities).
  • In the Search field in the Console’s toolbar, enter Sketch to filter for only Sketch related logs.
  • Launch Sketch and try to register the app with the license key in question.
  • Once the problem occurs again (in the case of a timeout this can take as long as 30 seconds) , return to the Console.
  • Select any of the messages listed in the Console window, then press Command-A to highlight all of the current logs.
  • Copy and paste the logs from the Console into a TextEdit file and save it.

Terminal results

There are a couple of terminal commands that you can use to test your connection to our server and what problems there are that could be causing that connection to fail. Follow these instructions to compile and send us your terminal results.

This first terminal command will tell you if you can connect to our api server, what certificate is used and if there is a proxy in between.

  • Launch the Terminal app (found in Applications > Utilities).
  • Press Command-N to open a new Terminal window.
  • Type curl -I -v https://api.sketchapp.com (or copy and paste it from here) and hit enter.
  • Click anywhere in the Terminal window, then press Command-A to highlight all of the text.
  • Copy and paste the text from the Terminal into a TextEdit file and save it.

The next terminal command is a tool provided by Apple that we can use to test the connection using different set of ATS (App transport security) configurations.

  • Launch the Terminal.app (found in Applications > Utilities).
  • Press Command-N to open a new Terminal window.
  • Type nscurl --verbose --ats-diagnostics https://api.sketchapp.com (or copy and paste it from here) and hit enter.
  • Click anywhere in the Terminal window, then press Command-A to highlight all of the text.
  • Copy and paste the text from the Terminal into a TextEdit file and save it.

Finally, fill out our support form and attach these three files—two with terminal results and one with your console logs—to your response. Once we have this information we can determine why you can’t connect to our server and try and solve your issue.

Remember, once you’ve registered Sketch you will be able to use the app while offline, but Sketch does need to connect to a network from time to time, in order to update the local license file and ensure your license is still valid. This will require a valid network connection as outlined above.

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