*123 results in fast busy?

I punch in *123 and I get a fast busy. For as far back as I can remember I've used *123 from my Voipo phone to access voicemail. What gives?

Our voicemail access code is 123 without the *.

http://voipo.com/help/article/star-c...e-list-19.html

Thanks, Tim. We can train ourselves to start using 123. All I can say is that *123 has worked for us until very recently.