Technical Tip: Unsupported protocol during HTTPS access: ERR_SSL_VERSION_OR_CIPHER_MISMATCH

[kajlasunil]

Description	This article describes the unsupported protocol during HTTPS access: ERR_SSL_VERSION_OR_CIPHER_MISMATCH
Scope	FortiGate.
Solution	The issue appears when a user is trying to get HTTPS access to FortiGate even if HTTPS and SSH access is allowed on the port. Error code: ERR_SSL_VERSION_OR_CIPHER_MISMATCH  This error occurs when the client and server do not support a common SSL protocol version or use an old TLS version. Related document: https://community.fortinet.com/t5/FortiCache/Technical-Tip-Low-Encryption-LENC-device-FAQ/ta-p/19032... To check the TLS version configured in the FortiGate use the below command: # sh full system global | grep tls     set admin-https-ssl-versions tlsv1-1 Config admin-https-ssl-versions to support more TLS protocols # config system global     set admin-https-ssl-versions tlsv1-2 end It is possible now, to try to access the GUI again: