When using a GoDaddy Multiple Domain (UCC/SAN) SSL Certificate between multiple sub-domains, you will see a 421 Misdirected Request Error.
The solution to the problem is entirely upon GoDaddy to perform. It’s in their deepest server configurations around SSL and how they’re handling your multi-domain certificate.
Server Name Indication
The solution is an extension to the SSL protocol called Server Name Indication (RFC 4366), which allows the client to include the requested hostname in the first message of its SSL handshake (connection setup). This allows the server to determine the correct named virtual host for the request and set the connection up accordingly from the start.
With SNI, you can have many virtual hosts sharing the same IP address and port, and each one can have its own unique certificate (and the rest of the configuration).
According to this article (How to Solve Frustrating 421 Misdirected Request Errors Forever), this is how you need to solve it:
So far, I've been unsuccessful in connecting with a GoDaddy Support Tech that understands the issue. The last two techs have said the issue is with our host and not GoDaddy, who is the SSL Provider.