These troubleshooting steps should help.
Work through them one at a time until you find the solution that solves your problem.
reset your Apple Watch.
After the restart, recheck your Contacts to see if the names have reappeared.
power cycle your iPhone.
you could reboot your Apple Watch and your iPhone simultaneously to make this process a little faster.
Check your Wi-Fi and Bluetooth connections.
If it’s not, then the contact information won’t be able to sync.
You’ll need toconnect your iPhone to Wi-Fiand turn on Bluetooth before trying to sync again.
Unpair your Apple Watchand then andreconnect it to your iPhone.
When you unpair your Apple Watch, it will remove all the apps and data from the watch.
Resync the data on your Apple Watch.
Check any third-party apps you have installed.
A third-party app could prevent syncing, especially if the app is having a problem.
Look for any apps with access to your Contacts andremove them altogether.
it’s possible for you to release the buttons when the Apple logo is displayed.
Once the restart is complete, check to see if your contacts are syncing properly.
When all else fails,an Apple Genius Bar appointmentmight be your best option for getting the issue fixed.
you’re free to get the help you better get your contacts showing up properly again.
If you’re not receiving any alerts at all, troubleshootissues with your Apple Watch notification configs.
If the setting is on, switch the toggle from off to on to resync your contacts list.
Also, ensure the correct account is associated with the Contacts app fromSettings>Contacts>Accounts.
