WhatsApp recently stated that registration on their platform is limited to mobile numbers only. However, they added that landline numbers can be used for registering with WhatsApp Business. This indicates that VoIP numbers such as UpCentral are not suitable for the registration process on WhatsApp.
Unsupported phone numbers can’t be registered on WhatsApp and include:
VoIP
Landlines
Toll-free numbers
Paid premium numbers
Universal access numbers (UAN)