red cicle with a red cross inside - IPod Classic (5th Gen)

I have a IPod Classic (5th generation) which I use time to time.

When I start it ... it seems to start normally, but after a while it display a red circle with a red cross inside ... with the indication www.apple.com/support/ipod

I tried all what I could find to restart, reset, restore ...

I can't see it on the latest ITunes version nor on file explorer.

Not sure what to do next !

Thanks for any support on this.