I can't get Viber (latest version) to start activation process on GrapheneOS Android 13 (clean wipe + flash) on Pixel 4a. Activation process works on GrapheneOS Android 12, but on Android 13 version it simply says "Activation Failed".
Viber tech support does not detect any activation attempts from my phone number. Enabling/Disabling VPN has no effect. Giving Viber full permissions also has no effect.
Viber does not erquire Google Play Services for push notifications or anything else.