Weak Diffihelman key
If a secure website gets the error ERR_SSL_WEAK_SERVER_EPHEMERAL_DH_KEY, it means the website is trying to set up a secure connection, but it is actually IN-secure because the SSL/TLS uses a Diffie-Hellman group size smaller than 1024-bit.
This is the problem in the Logjam vulnerability, which affects both browsers and servers: https://weakdh.org
In this case, the website/webserver needs to be fixed. So please contact the webserver administrator the disable weak DH keys and enable only strong Ciphers