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ERR_TLS_CERT_ALTNAME_FORMAT

tls cert altname format

What does this code mean?

Code ERR_TLS_CERT_ALTNAME_FORMAT · An issue reported by Node.js.

Official explanation · Original text

This error is thrown by checkServerIdentity if a user-supplied subjectaltname property violates encoding rules. Certificate objects produced by Node.js itself always comply with encoding rules and will never cause this error.

Troubleshooting and diagnostic links

First check that the document's product, version, and environment match your situation.

Source and terms of use

Errors | Node.js v26.13.1 Documentation ↗

Creator: Node.js contributors; Joyent, Inc. and other Node contributors
License: MIT License (Node.js documentation)
Checked on: 2026-11-12

Modifications: English prose extracted; whitespace normalized; Korean context and classified official links added. Python code examples not redistributed.

Source details · Original licenses and notices