Search doesn't find anything after Dec.19, 2016

Search doesn't find anything after Dec.19, 2016

Zoho Mail Search does not return any results after December 19, 2016.
Attached are the following snapshots:

01-Inbox-VideoInSenderAndSubject.jpg
02-OldVersionSearch-Dec19.jpg
03-NewVersionSearch-Dec19.jpg

In File 01, the keyword video appears in the sender field of the first email message, and it occurs in the subject field of the last email message.  Both emails are dated Jan. 27, 2017
File 02 shows that running the old version, results are only returned for email messages on Dec. 19th and earlier.
File 03 shows the same results running the new version of Zoho Mail.

I have tried using Advance Search, and I get the same results.
Since no one else is complaining about this, I assume the problem must be something in my account, or a setting.  But I cannot find anything that would cause this behavior.