iPhone SE 3rd gen on iOS 18.0.1 won't sync with iTunes

My new iPhone SE 3rd generation on iOS 18.0.1 won't sync with iTunes on my Windows laptop. iTunes recognizes the phone and backing up the phone to iTunes works fine. But it won't synchronize, so I can't get my Outlook calendar from the laptop synchronized with the iPhone.

When hitting the sync button in iTunes, the sync briefly starts and then quits. When going to Files > Devices, then "Synchronize" appears in gray and can't be chosen.

iTunes version is the current 12.13.3.

My iPhone SE 2nd generation which is still on iOS 17.7 can be backed up and synced with iTunes as usual without problems.

Any help or suggestions would be much appreciated.