2015 and there is still a problem. what helped me(o2 galaxy s5 lolipop android 5.0)
1. set 901 as vocemail number
- ie. contacts -> 3 dots -> calls -> voicemail settings -> voicemail numer
2. enable voicemail by dialing 1750
3. call voicemail then LISTEN TO THE LADY
after she'll tell you yoy...