Outlook is set up by default not to notify the user of new emails in an IMAP mail account. You’d need to set up a rule to be notified of new emails in your HyperOffice IMAP account in Outlook:
From the Tools menu, select Rules and Alerts.
The Rules and Alerts dialog appears. Click the New Rule button.
The Rules Wizard dialog appears. Select the Start from a blank rule option, then select Check messages when they arrive and click Next.
Check through the specified account.
Click specified in the ‘Apply this rule after the message arrives through the specified account and on this machine only’ in Step 2. The Account dialog appears. Select imap.hyperoffice.com and click Ok. Click Next.
Select the display a Desktop Alert option.
Select play a sound, then click on a sound in the ‘Apply this rule after the message arrives through the imap.hyperoffice.com account and on this machine only play a sound and display a Desktop Alert’ in Step 2.
Select the sound you want to play.
Click Next, then select Turn on this rule and click Finish.