Sync trouble without VPN

Synchronization problem. 

I'm connected to the Internet and using Lightroom Classic 11.4.1   

LR tells me a connection problem and all synchronization functions are not enabled. On the other hand, as soon as I launch the VPN that I use for teleworking, all these functions become active again and the synchronization works correctly.

What to do for sync works in any case, with or without VPN

in advance thank you for your help.