Intermittent errors with app installation token authentication

Summary

Intermittent errors with app installation token authentication

On May 23, 2026 between 06:00 UTC and 19:12 UTC, GitHub experienced intermittent errors authenticating <a href="https://docs.github.com/en/apps/creating-github-apps/authenticating-with-a-github-app/authenticating-as-a-github-app-installation" target="_blank">GitHub app installation tokens</a>. During this time, between 1-5% of app installation token authentication requests failed, with an average of 2.3% and the error rate peaking at approximately 5.4% around 14:00 UTC. Users may have experienced authentication failures when using GitHub Apps, including failures in Git operations and API calls using app installation tokens. The issue was caused by an issue in a caching proxy component and was remediated by rolling back that component to a previous version. We are taking steps to improve monitoring for cache miss anomalies to ensure that token authentication remains functional during infrastructure changes and reviewing our protocol for testing and when we upgrade third-party dependencies.

• Started

  May 23, 2026 · 4:00 PM

• Resolved

  May 23, 2026 · 7:32 PM

• Duration

  3h 31m

• Severity

  Minor

• ◐

  Investigating

  May 23 · 4:00 PM GitHub

  We are investigating reports of impacted performance for some GitHub services.

• ◐

  Investigating

  May 23 · 4:01 PM GitHub

  We are seeing an increased rate of authentication failures for app installation tokens, affecting approximately 1% of tokens.  We are continuing to investigate.

• ◐

  Investigating

  May 23 · 4:35 PM GitHub

  We are continuing to investigate an elevated error rate of authentication failures for app installation tokens.  Next update in one hour.

• ◐

  Investigating

  May 23 · 5:41 PM GitHub

  We are seeing signs of mitigation and are continuing to monitor for complete mitigation.  <br /><br />Next update in one hour.

• ◐

  Investigating

  May 23 · 6:42 PM GitHub

  We see significant signs of mitigation and are monitoring for full mitigation.

• ◐

  Investigating

  May 23 · 7:06 PM GitHub

  We have identified and are applying additional mitigation and will continue to monitor for complete mitigation.

• ◐

  Investigating

  May 23 · 7:32 PM GitHub

  This is fully mitigated, we will continue to monitor to ensure it does not reoccur.

• ✓

  Resolved

  May 23 · 7:32 PM GitHub

  On May 23, 2026 between 06:00 UTC and 19:12 UTC, GitHub experienced intermittent errors authenticating <a href="https://docs.github.com/en/apps/creating-github-apps/authenticating-with-a-github-app/authenticating-as-a-github-app-installation" target="_blank">GitHub app installation tokens</a>. During this time, between 1-5% of app installation token authentication requests failed, with an average of 2.3% and the error rate peaking at approximately 5.4% around 14:00 UTC. Users may have experienced authentication failures when using GitHub Apps, including failures in Git operations and API calls using app installation tokens. The issue was caused by an issue in a caching proxy component and was remediated by rolling back that component to a previous version. We are taking steps to improve monitoring for cache miss anomalies to ensure that token authentication remains functional during infrastructure changes and reviewing our protocol for testing and when we upgrade third-party dependencies.