It looks like Zotero isn't able to connect to part of the Amazon cloud for file syncing.
Most likely this is due to a proxy server or security software on your computer interfering with these requests.
It should normally display a different error for certificate problems, but start by checking the certificate info for s3.amazonaws.com, as explained there.
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Most likely this is due to a proxy server or security software on your computer interfering with these requests.
It should normally display a different error for certificate problems, but start by checking the certificate info for s3.amazonaws.com, as explained there.