Error Message in zoho docs: The server has encountered an error

We have a spreadsheet in the zoho docs area. Only two collaborators on the sheet. We keep on getting a yellow line across the top of the spreadsheet that says "The server has encountered an error. Please try again later."

While this error is up, I can still edit in the field, but I can't use any of the menu items.

The spreadsheet is also agonizingly slow to edit and move.

Is this a spreadsheet problem or a zoho problem?

Any help is appreciated.

Thanks.