When a 10-digit or 11-digit number appears in an email, the number can appear as a hyperlink so that you can call the number by using Skype or the default telephony provider on your operating system.
In order for 10-digit and 11-digit numbers to be identified as phone numbers, you must select a default telephony provider.
Click Tools > Options.
Double-click Environment, and then click the Default Actions tab.
In the Default telephony provider drop-down list, select one of the following options:
None: Displays phone numbers as regular text and not as hyperlinks.
Default Phone Dialer: Uses the default telephony provider on your operating system.
Skype: Uses Skype to make calls when clicking phone numbers.
For more information about making calls from GroupWise with Skype, see the GroupWise and Skype Quick Start.