What is causing "synchronizing folder list failed with an error: Execution of authentication request returned unexpected result: 404?

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Can+you+tell+me+what+is+causing+a+"synchronizing+folder+list+failed+with+an+error:+Execution+of+authentication+request+returned+unexpected+result:+404?+

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I did not type in the “+” signs.

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Hi Doreen, can you screenshot the error and copy the content of the Log tab (same window next to the error tab) here when this problem happens again?

Best regards,
Olivia