# security
## Entries3 knowledge objects
JWT signature verification failed: invalid signature
mediumThe token's signature did not verify against the key you supplied. The specification requires rejecting it outright — there is no partial trust — and the cause is almost always a key mismatch or an algorithm disagreement rather than a tampered token.
/k/jwt-signature-verification-failed · security · 2 sources · verified 2026-08-08 · JsonWebTokenError SignatureVerificationError
OAuth error redirect_uri_mismatch: redirect URI is not registered
highThe authorization server compares the redirect_uri you sent against the registered one with simple string comparison — byte for byte. A trailing slash, a different port, or http instead of https makes two URIs that look the same to a human not equal, and the spec requires the server to reject them.
/k/oauth-redirect-uri-mismatch · security · 3 sources · verified 2026-08-08 · redirect_uri_mismatch invalid_request
SSL certificate verify failed: unable to get local issuer certificate
mediumThe client could not build a trust chain from the server's certificate to a CA it trusts. Usually the server is not sending its intermediate certificate, or the client has no CA store at all — and the two look identical from the error message while needing opposite fixes.
/k/ssl-certificate-verify-failed · security · 2 sources · verified 2026-08-08 · CERTIFICATE_VERIFY_FAILED UNABLE_TO_GET_ISSUER_CERT_LOCALLY SELF_SIGNED_CERT_IN_CHAIN