There seems to be something broken with the linux 2.2.0 version and SSL handling for certain providers. I have similar issues with the B2 (Backblaze) - mentioned here: Backups fail with "The SSL connection could not be established" - #3 by Pawel_Wrona .
It even fails at the “Test connection” with this SSL error. Exactly the same configuration with 2.1.0.5 this works fine. I’ve also tested Windows version 2.2.0 of duplicati and it’s fine there.
And I also use Google (Google Cloud), where everything is working fine.