On iPhone:
- Ensure Wi-Fi Calling is disabled (via iPhone Settings -> Phone -> Wi-Fi Calling)
- Open your iPhone Contacts app
- Locate the 'Hullomail Activate' contact
- Call the activation code inside - This will try setup the call forwarding rules again
On Android:
- Ensure Wi-Fi Calling is disabled (via your Phone app -> Setting -> Wi-Fi Calling)
- Open the Hullomail app
- Go to Menu/Settings -> Voicemail activation
- Tap 'Activate voicemail' - This will try setup the call forwarding rules again