Fetch Mail don't get everything

Fetch Mail don't get everything

Hello, I'm using Imap in Zoho Virtual Office 3.0 and something curious is happening.... always when I fetch mail, is retrieved only 5 messages.

So, I have to fetch again and again to get more 5 messages for each time, and so on.... Detail: in this account, I have more than 100 messages in inbox folder.

Thank you!