The inbuilt Windows fat32 formatter does not cater for formatting drives greater than 32GB in size.
I haven't needed to format to FAT32 for anything larger than 32GB for a couple of years, partly due to its limitation of 4GB maximum size for an individual file. If that 4gb individual file limit is OK for you then you could try the FAT32 formater that I've used for drives from 64GB to 1TB.
http://tokiwa.qee.jp/EN/Fat32Formatter/
The other point to watch out for is to check that your USB3 SSD is USB2 compatible. If it doesn't state on the drive it self and you haven't got the original package then a quick google should come up with the answer.
Are you sure that film played OK before?