I am wanting to be able to access my voicemail directly from my phone.

I am using Grandstream GXP1400 phones.

The Grandstream manual says ...

"VOICE MESSAGES (MESSAGE WAITING INDICATOR)

A blinking red MWI (Message Waiting Indicator) on the top right corner of the phone indicates a message
is waiting. Dial into the voicemail box to retrieve the message by entering the voice mail number of the
server or pressing the Voicemail button (Voice Mail User ID has to be properly configured as the voice mail
number under Web GUI->Account x->General Settings). An IVR will prompt the user through the process
of message retrieval."

The web GUI configuration hint for Voice Mail UserID says

"Allows
users to access voice messages by pressing the MESSAGE button on the
phone. This ID is usually the VM portal access number."

Does this mean that in order to check voicemail directly from the phone I need to purchase an additional phone number to be the "VM portal access number" for each voicemail box I want to set up?

Hi Robert,

To setup your Voicemail dial *00 from your SIP phone.

You can then access/checkyour voicemail by dialing *98.

See here for more details: https://www.ringroost.com/how-to-set-up-voicemail.php

- No need for more numbers.