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curle_ech_required
Easy Fix
cURL · libcurl & CLI
libcurl code CURLE_ECH_REQUIRED indicates ech required during libcurl option/runtime call sequencing.
Quick Answer
Error code CURLE_ECH_REQUIRED on your cURL libcurl & CLI means: libcurl code CURLE_ECH_REQUIRED indicates ech required during libcurl option/runtime call sequencing.. This is usually fixable — see the step-by-step guide below.
Affected Models
Likely Causes
  1. CURLE_ECH_REQUIRED was returned while libcurl handled a request stage related to libcurl option/runtime call sequencing.
  2. Command options, endpoint behavior, or intermediary network components are incompatible with expected transfer flow.
  3. Runtime environment specifics (proxy, cert store, protocol support, or callback behavior) contributed to CURLE_ECH_REQUIRED.
How to Fix It
1
Capture verbose output (-v / --trace) and isolate the exact phase where CURLE_ECH_REQUIRED appears.
2
Reproduce ech_required with a minimal request against a known-good endpoint.
3
Validate protocol, TLS, DNS, proxy, and timeout options tied to libcurl option/runtime call sequencing.
4
Adjust one option at a time until CURLE_ECH_REQUIRED clears and transfer completes successfully.
5
Lock the fix into scripts/clients and monitor for CURLE_ECH_REQUIRED regression.
Pro Tip
This is a common issue that most users can resolve without specialized tools. Try the first step before moving on to more complex solutions.
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