What do "ERR_SSL_VERSION_OR_CIPHER_MISMATCH" and "no shared cipher" mean?
You may see errors like the following when trying to access certain services or sites.
(SSL_accept): error:1408A0C1:SSL routines:ssl3_get_client_hello:no shared cipher
SSL routines:SSL23_GET_CLIENT_HELLO:unkown protocol
This means that an SSL connection could not be established because there is no overlap between the SSL cipher suites or SSL protocols used by the service and the ones used by the client trying to connect to it. Typically this occurs when one of the two is outdated.
In order to resolve this, the outdated software will need to be updated to support newer ciphers. If for some reason it can't be updated, the SSL cipher suite on the newer software will need to be adjusted so that there are ciphers that can be used by both.
In the case that the SSL cipher suite needs to be adjusted, we have the following guide which covers cPanel/WHM, Apache, Dovecot, and Exim.
Where can I set Ciphers and TLS/SSL protocols in WHM?
If you are seeing such errors on Windows 7, the following article contains information about updating TLS support on Windows 7, which may resolve the issue.
Outlook TLS error: None of the authentication methods supported by this client are supported by your server.