I have a pixel 4a, running into latest stable version of GrapheneOS. My carrier is T-Mobile. I have Google services framework installed with no network access. I have read the carrier section under usage on GrapheneOS.org

I see no visual voicemail options in the stock dialer. All permissions enabled except camera, location, music and audio, nearby devices and photos and videos

Phone by Google is installed, latest version updated September 29th. All permissions enabled except location, nearby devices and network

Phone by Google looks like visual voicemail is active, but errors when trying to play a voicemail with unsupported message type and couldn't play voicemail. There is no text version of any voicemail.

Do I need to install another app?

Does Phone by Google need network permission? I'd rather do without visual voicemail if it means sending data to Google.

Any other settings I should try?

Many thanks in advance

    fuhgeddaboudit

    from the website

    GrapheneOS aims to work with all carriers that are officially supported by Google on the stock operating system on Pixel devices. Wi-Fi Calling, VoLTE, Visual Voicemail, MMS, SMS, Calling and 5G (SA and NSA) all are supported, however some functionality may not be usable due to Google not supporting carriers on the stock OS officially or due to GrapheneOS not shipping proprietary apps required in order for this functionality to work on some carriers. GrapheneOS extracts CarrierConfigs, APNs, modem configurations, Visual Voicemail configurations and MMS configurations from the stock operating system to ensure users get easy carrier support that "just works".

    If you are having issues with Visual Voicemail, please be aware that AT&T USA users are unable to use this feature currently due to a lack of AOSP support. Other carriers are done on a best effort basis. We would suggest using Google Dialer with sandboxed Google Play if you are unable to get this feature working.

    It says you need Google Play for it to work, so to fix it I'd do these things:

    1. uninstall Google Dialer
    2. install Google Play from the "Apps" app (you don't have to log in if you don't want to)
    3. reinstall Google Dialer
    4. Try visual voicemail again

    I don't know if visual voicemail or Google Play Services require internet connectivity for this to work. I don't have visual voicemail, personally. I'd try it with network permissions on for both Play Services and Google Dialer first then remove the permissions if you really want to.