Increased Function Invocation Errors - ERR_MODULE_NOT_FOUND

Incident Report for Vercel

Resolved

This incident has been resolved.

Some deployments created between May 18, 2026, 06:15 PM - 10:16 PM UTC may have experienced increased ERR_MODULE_NOT_FOUND function invocation errors due to a bad rollout. Deployments created outside of this window are unaffected.

The fix is being rolled out to existing deployments retrospectively and is expected to finish in the next few hours.
Posted May 18, 2026 - 23:52 UTC

Update

We are continuing to monitor for any further issues.
Posted May 18, 2026 - 22:19 UTC

Monitoring

A fix is rolled out for the function invocation errors affecting React Router 7 deployments. To recover, redeploy your application or use Instant Rollback to a previous deployment from the dashboard. We're continuing to monitor.
Posted May 18, 2026 - 22:16 UTC

Update

We're continuing to work on rolling out a fix. In the mean time, customers may use Instant Rollback to a previous deployment version as an immediate workaround in order to recover.
Posted May 18, 2026 - 22:11 UTC

Identified

The issue has been identified and a fix is being implemented.
Posted May 18, 2026 - 21:53 UTC

Investigating

We're investigating an issue where customers are currently experiencing application failures due to function invocation errors when using React Router 7.
Posted May 18, 2026 - 21:42 UTC