WD My Book 8TB fails

I used My Book whole week, No problems.
Today it did not appear on my screen. The diskhelpprogram on my iMac shows the disk, but it is not activated.
I formatted in ex-FAT the disk as I bought it new last month, so it could be used on Mac en in Windows.
Where do I have to look?

If you need a server for mac and pc you will need one that uses SAMBA so it can be used like you want

What do you mean by server?

https://www.hardcoregames.ca/2020/09/10/synology-diskstation-ds1621xs/