What does it mean when I m dialing a number, then entering an extension and it hangs up on me after it says it s dialing the extension?

Yesterday I dialed a 1800 number to speak with a woman who gave me her extension to verify my indenity for taxes, and the extension worked and allowed me to leave a message. Today she called me back, and now when I try to call her back after I enter the extension it hangs up on me.


Maybe her voicemail box is full, and so, the call has nothing else it can do, so it just drops.