ML6000 connection issues

I'm trying to update the firmware on my library. I got it several years ago, but am only now getting to setting it up. 
I think the biggest problem I'm running in to is that it's running an ungodly old firmware. 320G-GS004.
I am unable to get into the remote management interface. I have tried multiple browsers (including a very old version of firefox) and always get "{IP} refused to connect" and ERR_CONNECTION_REFUSED. I already ran the Library Service Utility update as well and it finished successfully (supposedly). 
I have tried logging in via SSH with putty, but keep getting access denied with proper login credentials, with multiple user accounts (I created a second admin level user on the touch interface).

I have a suspicion that this is due to not being able to set the correct date on the enclosure, but I can't be sure. The firmware is so old that I can't configure a date newer than the year 2020 with the onboard interface (Thatwas a great idea...). 

I have not yet tried the serial interface nor the service ethernet port, as I haven't found much documentation on it and would like to avoid creating a 50+ pound doorstop. 

Any assistance or advice would be very helpful with this. 
Thank you very much.