GitHub Authentication Issues for Some Users
Monitoring - GitHub has deployed a mitigation that should improve the GitHub API token issues. We have also pushed an update to CS50 Codespace to accommodate these changes. Please update your Codespace immediately when prompted, or run update50 in your Codespace.

For Codespaces that boot into recovery mode (e.g., where none of the submit50 or check50 tools are available), please follow this documentation to fix the Codespace, then update it to the latest version: https://cs50.readthedocs.io/cs50.dev/#codespaces-run-into-recovery-mode
Aug 24, 2026 - 12:07 EDT
Update - We've learned that this issue involves GitHub components that are beyond our control. In affected cases, the GitHub account would have encountered the rate limit regardless of how the Codespace was accessed.

As a workaround, you can configure GitHub SSH, which should allow tools such as submit50 and check50 to work:

https://cs50.readthedocs.io/github/#ssh

CS50 Duck inside Codespaces may also be affected by this issue. In the meantime, https://cs50.ai remains operational.
Aug 22, 2026 - 08:23 EDT
Update - We have been working with GitHub to address the issue, but for the moment, if you are experiencing GitHub token issues (either an invalid token or your GitHub account being rate-limited), please do the following:

1. If your Codespace prompts you to update, please run update50 to update your Codespace immediately.
2. If you are unable to access your Codespace because your GitHub account is being rate-limited, please close all Codespace browser windows and tabs and stop interacting with github.com in any way. Wait one hour, then visit https://cs50.dev to access your Codespace.
3. If you are already running the latest version of CS50 Codespace but are still experiencing a GitHub token issue, please take a screenshot of the error message and email it to sysadmins@cs50.harvard.edu, along with your GitHub username and the content of https://cs50.dev/debug

If your Codespace is up to date and your GitHub account is not rate-limited, yet the token issue still persists, please do the following:

1. Visit https://github.com/settings/connections/applications/d1a90a524497a69391fa
2. Click "Revoke access" to revoke access for cs50.dev.
3. Then visit https://cs50.dev/restart. You should be prompted to authorize access; please authorize it again.
Aug 22, 2026 - 07:42 EDT
Update - We are continuing to work on a fix.

1. If your Codespace prompts you to update, please do so immediately.
2. If you are unable to access your Codespace, please close all Codespace browser windows and tabs, wait one hour, then visit https://cs50.dev and update your Codespace.
3. If you are already running the latest version of CS50 Codespace but are still experiencing a GitHub token issue, please take a screenshot of the error message and email it to sysadmins@cs50.harvard.edu, along with your GitHub username.
Aug 21, 2026 - 12:32 EDT
Identified - We have identified the issue and are currently working on a fix.

As a workaround, please do the following:

1. Visit https://github.com/settings/connections/applications/d1a90a524497a69391fa
2. Click “Revoke access” to revoke access for cs50.dev.
3. Then visit https://cs50.dev/restart again. You should be prompted to authorize access; please authorize it again.
4. Wait for your Codespace to restart and see if that resolves the problem.
Aug 20, 2026 - 21:16 EDT
Investigating - We are currently investigating this issue.
Aug 20, 2026 - 07:23 EDT

About This Site

This is CS50's status page, which summarizes which of CS50's services are currently operational. If some service appears to be operational below, but you think that there is, in fact, an outage, please email sysadmins@cs50.harvard.edu with specific details!

For help with any of CS50's assignments, problem sets, or projects, best to post in any of CS50's communities!

api.cs50.io Operational
cdn.cs50.net Operational
certificates.cs50.io Operational
check50 Degraded Performance
cli50 Operational
cs50.ai Operational
cs50.courses Operational
cs50.dev Degraded Performance
cs50.edx.org Operational
cs50.harvard.edu Operational
cs50.readthedocs.io Operational
cs50.ly Operational
cs50.me Operational
forms.cs50.io Operational
harvard.cs50.me Operational
help50 Operational
id.cs50.io Operational
manual.cs50.io Operational
render.cs50.io Operational
render50 Operational
style50 Operational
submit.cs50.io Operational
submit50 Degraded Performance
time.cs50.io Operational
vault.cs50.io Operational
video.cs50.io Operational
and third-party services... Degraded Performance
Auth0 Management API Operational
Auth0 User Authentication Operational
AWS EC2 (us-east-1) Operational
AWS EC2 (us-west-2) Operational
AWS ELB (us-east-1) Operational
AWS Lambda (us-east-1) Operational
AWS RDS (us-east-1) Operational
Cloud 9 (us-west-2) Operational
edX Operational
GitHub Actions Operational
GitHub API Requests Operational
GitHub Codespaces Operational
GitHub Copilot Operational
GitHub Git Operations Operational
GitHub Issues Operational
GitHub Notifications Operational
GitHub Packages Operational
GitHub Pages Operational
GitHub Pull Requests Operational
GitHub Webhooks Operational
Google Cloud Platform Google Cloud Networking Operational
HUIT Operational
Netlify API Operational
Netlify Build Pipeline Operational
Netlify Content Distribution Network Operational
OpenAI API Operational
PyPi Operational
Slack Connections Operational
Slack Login Operational
Slack Messaging Degraded Performance
Zapier Operational
Zoom Meetings Operational
Zoom Software Operational
Operational
Degraded Performance
Partial Outage
Major Outage
Maintenance

Aug 25, 2026

No incidents reported today.

Aug 24, 2026

Unresolved incident: GitHub Authentication Issues for Some Users.

Aug 23, 2026

No incidents reported.

Aug 22, 2026

Aug 21, 2026

Aug 20, 2026

Aug 19, 2026

No incidents reported.

Aug 18, 2026

No incidents reported.

Aug 17, 2026

No incidents reported.

Aug 16, 2026

No incidents reported.

Aug 15, 2026

No incidents reported.

Aug 14, 2026

No incidents reported.

Aug 13, 2026

No incidents reported.

Aug 12, 2026

No incidents reported.

Aug 11, 2026

No incidents reported.

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