Contacts search not working

On the Zoho website the search function in contacts is no longer working. If I enter a name in the search box and hit return I see popups with 'Searching' and 'Loading', but no results are displayed.

I know the contact is in the database. I can see it if I scroll through.

I definitely selected 'Search all contacts'. I have tried all the options - 'Search all fields', 'Name' 'Email' etc. This happens with several different conatcts.

Any idea what is wrong?