I created a Zoho sheet, saved it, and shared it with one person, read/write setting. I sent an invitation to that person. Clicking on the link in the received invitation, takes you to the sheet but there is no option to save it, even though was shared with read/write permissions. So I tried again, but this time when I send the invitation, the shared user never gets the invitation email. So now I can't invite, and when I do, that shared person can't save their changes. What gives?