Riverside Retro 2017 toilet leak

Hello,

I’ve had this parked a year and noticed a leak coming from the back of the toilet.  Having difficulty finding out the toilet model and none of the diagrams on the website match my layout.  Calls to the company at 260-499-4578 don’t go through, no email address to be found.  I am stumped.  Does anyone know the toilet model and/or have suggestions as to how to fix it?

Thank you!