{"type":"https://developers.cloudflare.com/support/troubleshooting/http-status-codes/cloudflare-5xx-errors/error-521/","title":"Error 521: Web server is down","status":521,"detail":"Cloudflare attempted to connect to the origin web server, but the connection was refused. The origin is down, blocking Cloudflare IPs, or not accepting connections on the configured port.","instance":"a1dab73f499b610f","error_code":521,"error_name":"origin_down","error_category":"origin","ray_id":"a1dab73f499b610f","timestamp":"2026-07-19T15:21:28Z","zone":"api.divar.ir","cloudflare_error":true,"retryable":true,"retry_after":120,"owner_action_required":true,"what_you_should_do":"**Wait and retry.** Back off for at least 120 seconds. If the error persists, the origin is offline or blocking Cloudflare — the website operator must restart the origin or whitelist Cloudflare IPs.","footer":"This error was generated by Cloudflare on behalf of the website owner."}