Voicemail uses "the person at extension is not available"

Hello, I have two extension working. I use the ring groups for each of them and when not answered I have them set up to an announcement and then to voicemail when finished however one them works perfectly but the other when it goes to the announcement it just picks up the first part or word and then it goes to the unavailable message.

There may be something I’m missing but I have them set up the same, how can I stop the unavailable system message from playing.

Thanks.

Need help on this one, anybody? Thanks again.