zhizhu
Home / developer-tools / Fix Windows Update Error 0x80070005 with Registry Tweaks - Cloudflare 521 Error After Update: Fixes That Work-Resolve NO_PUBKEY and Invalid Signature Errors in Ubuntu

Fix Windows Update Error 0x80070005 with Registry Tweaks - Cloudflare 521 Error After Update: Fixes That Work-Resolve NO_PUBKEY and Invalid Signature Errors in Ubuntu

2026-06-13 11:41:02developer-tools
Fix Windows Update Error 0x80070005 with Registry Tweaks - Cloudflare 521 Error After Update: Fixes That Work-Resolve NO_PUBKEY and Invalid Signature Errors in Ubuntu

Final checklist

  • Confirm that the same symptom is gone after a restart or refresh.
  • Keep the smallest working change and undo temporary diagnostic settings.