The culprit was incompatibility between request arguments within Fastly, and on our origin servers. This has been remedied.

The culprit has been identified as related to how the Fastly CDN is interpreting Accept-Encoding headers, notably when served compressed content. We're working on a resolution.

Roughly 1-3% of traffic is impacted. It is only impacting repo metadata fetches, and dnf itself is not impacted - it appears mostly to be impacting various API-like requests from automated systems depending on how the client structures its request headers.

repo.almalinux.org is intermittently serving 501 responses to requests. We are looking into this.

Note: this issue was reported and confirmed on March 3, 2026 but we backdated this issue to represent when the issue began.