I switched to a Note4 from an s5 Active last week.. not sure if it's related to the device switch but none of the third party voicemail apps will work anymore. I been using YouMail for over a year and can no longer access their service, or any other 3rd party vm app for that matter. I called ATT and we went through various settings at length but I was told the issue lies with the 3rd party app. I just find it hard to believe that none of the 3p voicemail apps will work so there has to be something else going on. I can still use the default voicemail which works okay. Here are a couple of screen shots of what I've been dealing with. One is the error code with YouMail, the other with Visual Voicemail during set-up. Anyone out there can help me? I have no idea what the issue is.