Sync between Lightroom Classic and iPhone app doesn't work anymore

I've been syncing a lot of photos during the last year between my Lightroom Classic (13.5.1) and iPhone but suddenly this process stopped working. Can't find the problem, anyone who can help me?

It only say: "syncing" but nothing happens for hours. Sometimes it works when i shut down Lightroom on my computer but then when I select new photos to sync it stops again.

Mac OS Monteray 12.7.5

iPhone 15 Pro iOS 17.6.1