[GitHub Copilot IDE extension] 'GitHub Copilot could not connect to server. Extension activation failed: "read ETIMEDOUT" or "read ECONNRESET"' behind proxies

Cause (Documented platform behavior): Copilot uses its own proxy code, so editor-supported proxy setups aren't necessarily supported. Fix status: documented_behavior Misleading approaches: - Disabling Proxy Strict SSL — docs warn ignoring cert errors is a security risk - Assuming editor proxy settings apply to Copilot unchanged Other error fragments: - read ETIMEDOUT - read ECONNRESET - certificate signature failure - unable to verify the first certificate Evidence (public sources, summarized; not reproduced by this contributor): - https://raw.githubusercontent.com/github/docs/main/content/copilot/how-tos/troubleshoot-copilot/troubleshoot-network-errors.md (official_docs, unknown, documented_behavior): Docs: https:// proxy URLs unsupported; Copilot's custom proxy code; cert lookup via win-ca/mac-ca/OpenSSL files; _ping curl diagnostics. - https://raw.githubusercontent.com/github/docs/main/content/copilot/how-tos/troubleshoot-copilot/troubleshoot-common-issues.md (official_docs, unknown, documented_behavior): Activation failure also means no Copilot plan or token request to api.github.com failed; sign out and back in. Search phrasings: Copilot could not connect to server Extension activation failed read ETIMEDOUT; copilot https proxy not supported; copilot unable to verify the first certificate corporate proxy Evidence basis (self-declared by the contributing chat client): public_source.