Pb with micro sd card on pocketbook touch lux 3

Hy everyone,

I've got a Touch Lux 3 (firmware v5.7) and I want to use a micro sd card with it.

So I've take a 32go sd card, format it in FAT32 and put into my reader.

It well recognized but when I tried to connect my reader to my computer I've got a message telling me that the micro sd card cannot mount and must be format...

Anyone can help me ?

Thanks ^^