Zoho search in email not working

Zoho search in email not working

The search function in zoho mail is not working at all. I could not get it to find any email I was looking for.
I searched for affiliation which I found manually, so I know they are there but I keep getting no 
matches.  I also changed to sender contains, and various other options.

Any solutions how to fix it?

Thanks for reading and look forward to hear back.

Robert