can you open your Ubisoft Connect directory in C:\Program Files(x86)\Ubisoft\Ubisoft Connect\Logs and check the launcher log.
Do you get something similar to
[14128] 2020-12-18 00:18:54 [18888] ERROR SSLSocket.cpp (527) Certificate verification for host 'dmx.upc.ubisoft.com' failed: 2148081683
[14128] 2020-12-18 00:18:54 [18888] ERROR SSLSocket.cpp (531) CA, H2T 1S6, Quebec, Montreal, "5505 Blvd St-Laurent, suite 5000", Ubisoft Divertissement Inc, Uplay, dmx.upc.ubisoft.com
[14128] 2020-12-18 00:18:54 [18888] INFO SSLSocket.cpp (434) Certificate verification failed, closing connection.
[14128] 2020-12-18 00:19:54 [18888] ERROR SSLSocket.cpp (527) Certificate verification for host 'dmx.upc.ubisoft.com' failed: 2148081683
[14128] 2020-12-18 00:19:54 [18888] ERROR SSLSocket.cpp (531) CA, H2T 1S6, Quebec, Montreal, "5505 Blvd St-Laurent, suite 5000", Ubisoft Divertissement Inc, Uplay, dmx.upc.ubisoft.com
[14128] 2020-12-18 00:19:54 [18888] INFO SSLSocket.cpp (434) Certificate verification failed, closing connection.
It must be related to CA Certificate not being trusted. Damn Ubisoft CC doesnt have any clue what to do to solve it. Hate this