Web lab not loading for students

Web lab is not loading for students, they just get the error “Web lab failed to load” I went to the troubleshooting page and had students clear their cookies/history. They are not browsing privately, they have their browsers updated. (This randomly happens to students, one day it will work, the other it won’t.)

I am just wondering if this is something I have to go to my IT department about or if it is on code.org’s end. Any help or insight into this issue as I am in class with very disappointed students right now, would be greatly appreciated!!


Sorry. This would be frustrating. I haven’t heard of any issues on the code.org side of things, but if you contact support@code.org, that will be an easier way to alert the engineers of any potential issues.

I have had similar things happen (not with the code.org site, but with other sites) and usually it turns out to be a district IT issue with the filters they use blocking one of the companion sites.

This page shows requirements including a few domains that should be unblocked for web lab to work (if you scroll down a little). You may want to have your IT folks check it out.

Good luck!


Hello @krea ! Sorry to hear your students have run into issues with WebLab not loading. As Mike mentioned above, we’ve seen similar reports over the years, most of which were all tied to school’s network / firewall settings blocking or preventing WebLab from loading as intended.

We’d encourage checking that list at IT Requirements | Code.org to ensure all sites listed there are marked as safe/allowed on your network(s). We especially make note of this because we’ve just recently added another new site to this list in the last few weeks: https://www.googleoptimize.com/, which we’ve seen reported leading to slowdown / blocking of WebLab from other schools recently.

Many schools that use Code.org also employ content filtering/firewall services, which can lead to slowdown or otherwise affecting how in our content loads for students, which is most frequently reported in WebLab. Examples of such services we’ve heard that were blocking or otherwise flagged our content in some form as of recently, include: GoGuardian, Lightspeed, Windows Defender, Akamai, Securly, and Cisco. Please contact us at support@code.org with any further details there, and we can investigate further!

Josh at Code.org
Senior Program Manager