What is please wait while voicemail is being downloaded?

"Please wait while voicemail is being downloaded" is a message that appears on a device when the user is attempting to access their voicemail. When the user receives a voicemail, the message is stored on the server of their phone service provider. In order to listen to the voicemail message, the user's device must download the audio file from the server. This process can take a few seconds to a few minutes, depending on the size of the audio file and the speed of the internet connection. During this time, the user is prompted to wait until the message has been fully downloaded before they can access and listen to it.