Unfortunately, you can't use the GrandCalls application, because UAE is one of the countries that blocked the VOIP services. Other countries that doesn't allow the VOIP communication are: China, Oman, Syria, Turkey, Malaysia, Bahrain, Belize, Iran, Kuwait, Libya, North Korea, Pakistan, Thailand, Tunisia and Vietnam. For further information you can get in touch with the software developer using [email protected]
email address.