Auth0 has 14 cipher suites scheduled for removal at the end of H1 2026. If any of your clients — your backend, a reverse proxy, an older mobile binary — negotiates one of them today, your next Auth0 call after the cutoff will fail with handshake_failure and no further explanation.

There's no JSON error body. No HTTP status code. No entry in the Auth0 tenant log, because the connection never gets far enough to hit the application layer. The client just gets a TLS alert from the edge and a stack trace that points at your HTTP library, not at Auth0.

That's a bad failure mode to debug under pressure, so it's worth checking now.

The exact suites being removed

Auth0's support article lists 14 CBC-mode and RSA-keyed suites as deprecated:

TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256 TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384 TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256…