Q: Connexion au serveur impossible

Hi,

Restart your iPhone then try pairing again.

Server status for Apple ID is working here >  https://www.apple.com/support/systemstatus/

Also,   Before you begin:

• To pair your Apple Watch, you need an iPhone 5 or later and the latest version of iOS.
• On your iPhone, go to Settings > Bluetooth and make sure Bluetooth is on.
• Make sure your iPhone is connected to Wi-Fi or a cellular network.
• Turn on your Apple Watch by pressing and holding the side button next to the Digital Crown until you see the Apple logo.
• Make sure both devices are charged and keep them close together as you pair and sync them.

From here >  Set up your Apple Watch - Apple Support

And for use in the future >   Apple Watch User Guide

Hi

Some other users reported experiencing a similar server communication error message earlier today, when trying to unpair their watches (seemingly associated with Activation Lock). This occurred despite Apple's public server status page reporting no apparent issues.

If the issue still persists, I suggest that you contact Apple Support for more information and assistance:

Contact - Official Apple Support

https://twitter.com/applesupport

Otherwise, you may prefer to try pairing your watch again later.

More information:

About Activation Lock on Apple Watch - Apple Support