Unable to log in when running KB in an iframe

I am trying to run KanBoard in an iFrame (server hosted on external server with the iFrame running on an internal system so users can access it internally. I can get the logon page to load, but entering my KB credentials just prompts I need a user ID and password. Any clue how to get KB inside an iFrame to actually pass the logon credentials?

We do not use oauth or any other user manager aside from what is built into KB.

Thanks in advance!