Tuesday, December 29, 2015

Firefox CUCM SSL Handshake Error

Firefox Error:
Secure Connection Failed
An error occurred during a connection to <IP ADDRESS of CUCM>. SSL peer rejected a handshake message for unacceptable content. (Error code: ssl_error_illegal_parameter_alert)

In Firefox:
Open About:Config
Search for “security.tls
Edit security.tls.insecure_fallback_hosts and add the <IP ADDRESS of CUCM>
Edit security.tls.version.fallback-limit and set to 0
Edit security.tls.version.min and set to 0


  1. This fixed an issue with self care portal login. Thanks!

  2. Thank you for your valuable trick!
    However, I got the issue back with CUCM 11.5 / Firefox 47.0

    None on the workaround succeded :(