Chalk me up as another with this problem, that has suddenly appeared.
I suspect that this is due to the fact that my corporate proxy requires a username/password and we are not allowed to add this to our system settings/keychain - we can only use applications that support supplying this info in their settings e.g. Postman, IntelliJ IDEA, or are capable of displaying an authentication popup like Chrome does for example.
I’m not sure why Obsidian have decided not to properly support proxy authentication (Proxy setting), seems rather short-sighted for a productivity tool, but sadly this might be the nail in the coffin for me if not fixed. I can live without Obsidian Sync (although I’d prefer not to have to, I don’t know why they don’t want my money), but I can’t deal with this popping up all day.