Cannot connect to Amazon account

My Mum has given me her old kindle. It’s connected to the wifi but can’t connect to my Amazon account. I think it may have missed a software update but the option to check for upgrades is greyed out (I think because I’m not logged in). I’ve reset many times & tried turning my Amazon account to “stay logged in”. Also tried plugging it into my laptop but no option to manually upgrade the software.

Any help would be great. Thanks