Impossible to find files on the server after client hard drive reset

Dear all,

I have a big issue. Nextcloud client for Windows was installed on my laptop.
I have put many files in it (it means they should be on the server too).
However after a hard drive (from my laptop) reset (partition deleted), I can’t find any of the latest files on my Server.

I suspect the client folder was deleted so the client folders too by Sync but I am not sure.

How to recover those files ? Thank you very much.

I have found why : it is because Nextcloud Client was syncing to the wrong IP adress. So :
Wrong IP -> Files only in local -> Partition deleted -> no File on server (good IP).

Nextcloud client for Windows said nothing about failing to sync. This is where there is a room for improvement for Nextcloud.