Cannot access search function for mail on mail.zoho.com

Cannot access search function for mail on mail.zoho.com

My search function seems to be disabled since yesterday, and is no longer allowing me to search for any keywords whatsoever.  I am showing just one keyword below, however I cannot get any results with any search terms at all.

Here are all the settings I am aware of to configure search parameters:



What has changed? Why can't I access the search function on my email any more?