Auth0 is about to start returning handshake_failure — how to tell if you're affected

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 t