CLASS101 Help Center

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Class Video Issues

#Lecture Playback Error

We apologize for the inconvenience

Please check your compatibility of devices, OS, and browser/apps below.

[Available Devices, OS, and Browser/Application]

※ You may face difficulties when using unsupported device or browser, so please check playable devices and browsers first.

※ As of December 8, 2022, videos may not play properly on some devices due to DRM (Digital rights management) issues. If you encounter the error code (Code7110·Code5·Code3) on the screen, please make sure to follow the steps below.

[When using Chrome]

If you see the error code 7110, please update your Chrome browser to the latest version.

How to update your Chrome browser to the latest version? Please go to step #2 below.

*After updating your Chrome browser, please follow step #1 to delete the cookie and cache data.

If you still see the error after following step # 1 and 2, please check if you use one of the below:

1. Device mirroring/sidecar function is in use.

2. VPN (IP Shared VPN Service) in use

3. Security software app (including virus protection software), Chrome extension program, a firewall running

If you are using an iPad, the video may not be played properly with the Chrome browser. Please use another browser such as Safari, Firefox, etc for your iPad. If the problem still persists, please play it with a PC.

  • Please check your VPN or Firewall

    • Using a VPN may cause an error when playing the video, so please make sure your VPN is off when playing the video.

    • Any security program, Chrome extensions, or firewalls may cause an error when playing a video, so please try to turn them off when playing the video.

If you are still having trouble taking classes on a playable device, please follow the tips below.

  1. Please clear the cookies and cache data from your Chrome browser.

    • Please set all data and delete data.

      • Enter "chrome://settings/clearBrowserData" on Google Chrome address bar.

      • Please delete the "whole period".

  2. Please update your Chrome browser to the latest version. (Step 3 will be automatically applied)

    • Enter "chrome://settings/help" on Google Chrome address bar → Check the current version and update (if applicable).

    • Please keep your browser up-to-date for a seamless learning experience.

  3. If the video freezes frequently, please disable "Use hardware acceleration when available".

    • Enter "chrome://settings/system" on Google Chrome address bar.

    • Disable "Use hardware acceleration when available" → restart your browser.

  4. Check your antivirus software, Chrome extensions, and firewalls.

    • Temporarily disable your antivirus software and try to re-access the video.

    • Enter "chrome://extensions" on Google Chrome address bar → turn off all extensions and re-access the video.