So the issue for me was solved once I started to use bucket name instead of bucket id.<p>The latter was mentioned in online docs here: <a href="https:&#x2F;&#x2F;www.backblaze.com&#x2F;b2&#x2F;docs&#x2F;quick_command_line.html" rel="nofollow">https:&#x2F;&#x2F;www.backblaze.com&#x2F;b2&#x2F;docs&#x2F;quick_command_line.html</a> but seems it&#x27;s REALLY outdated.