Uninstall Samsung Pay. It's the ONLY solution I've tried that worked. They don't play well together, not sure why, someone needs to tell Verizon and get Samsung to fix it asap.
equake, we want to make sure we can help you hear your voicemails without any interruptions and can assure we have reported this issue to our team. They have indicated a fix for this issue in the next update.
However, a few workarounds have been reported to work. One includes exiting and re launching the app. There are also particular applications that are known to interfere with the Visual Voicemail app. We suggest testing your S8 in Safe Mode to determine if this is a cause. Lets Restart in Safe Mode - Samsung Galaxy S8 / S8+ | Verizon Wireless and then keep us posted with your progress.