If you're unable to open a FlexBook®, the issue is often related to your internet connection, browser, device or account. The troubleshooting steps below can help resolve most access issues.
Internet Connection Issues
FlexBooks are accessed online and require a stable internet connection. If your connection is slow or interrupted, the book may not load properly.
Try this:
- Refresh the page.
- Check your internet connection.
- Switch to a different network if available.
Browser Compatibility
CK-12 works best with modern web browsers, including:
- Google Chrome (recommended)
- Microsoft Edge
- Mozilla Firefox
- Safari
If you're using an older or unsupported browser, try updating it or opening the FlexBook in a different browser.
Cached Data or Cookies
Stored browser data can sometimes interfere with loading content.
Try this:
- Clear your browser's cache and cookies.
- Close and reopen your browser.
- Sign in to CK-12 again.
Browser Extensions
Ad blockers, pop-up blockers, or privacy extensions may prevent certain CK-12 content from loading.
Try this:
- Disable browser extensions temporarily.
- Open the FlexBook in an incognito/private browsing window.
- Allow pop-ups if prompted.
Device or Operating System
Make sure your device and operating system are up to date. Older devices or outdated software may experience loading or display issues.
Temporary Service Issue
Occasionally, CK-12 may perform maintenance or experience temporary service interruptions. If the problem affects multiple FlexBooks or persists after troubleshooting, try again later.
I Can Open Other Pages, But Not One FlexBook
If only one FlexBook won't open:
- Refresh the page.
- Try opening the FlexBook from a different browser or device.
- Verify the link is correct and hasn't been modified.
- If the FlexBook was shared with you, ask the sender to confirm the link is still valid.
I'm Accessing CK-12 Through My School
If you're using Canvas, Schoology, or Google Classroom:
- Launch the FlexBook directly from your LMS.
- Make sure you're signed in with the correct school account.
- If your school manages access to CK-12, contact your teacher if the issue continues.
If you still cannot open a FlexBook after trying to troubleshoot, please contact support@ck12.org; please include the following information:
- URL of the FlexBook
- Your device and operating system
- Your browser and version
- A screenshot of any error message (if available)
- A description of what happens when you try to open the FlexBook
This information will help the team diagnose the issue quickly.