I found the solution for the visual voicemail issue I had. The problem was when I transferred all the data from my old phone to the new one, the contacts and messages were not synced to my Google account.
If you have the same issue with the visual voicemail not setting up try this.
On both phones, Go to settings, Accounts and backup, find Smart switch, click on Transfer data for device set up.
Choose wireless send from old to new, the transfer will start, it will ask which data to transfer, choose messages and text only.
As it's transferring, Choose to synced to your Google account, once it's done, give it a minute.
Open your visual voicemail app and follow instructions, after it refreshes you should be able to use your visual voicemail
