iPad not syncing with MacBook - server may not exist

I want to sync my iPad with my MacBook (photos, music, etc.).

It starts to back up - fine.

Then it wants to sync tracks - and stops with a popup saying "There was a problem connecting to the server "xxx.xxx.x.xxx" - The server may not exist or it is unavailable at this time..."

Well, indeed the server does no longer exist, nor does the IP address.

When I press OK in that message it comes up with a pop-up saying "The iPad "xxxxx" could not be synced because the sync session failed to finish."

How can I resolve that?

Where can I delete the non-existing server?

I've looked everywhere for a solution...

I'm running Sonoma 14.5 on my MacBook an the latest iPad OS.

Thanks in advance