The hosted runner lost communication with the server. Anything in your workflow that terminates the runner process, starves it for CPU/Memory, or blocks its network access can cause this error.

Starting April 2026, the CodeQL Action will skip computing file coverage information on pull requests to improve analysis performance. File coverage information will still be computed on non-PR analyses. To opt out of this change, create a custom repository property with the name `github-codeql-file-coverage-on-prs` and the type "True/false", then set this property to `true` in the repository's settings.