The One Voice mobile app turns your phone into a full softphone. You sign in with your existing The One Hub account and can place and receive business calls, see recent calls, send and read messages, and check voicemail — all from your mobile device. Incoming calls ring with the native call screen (CallKit on iOS) even when the app is closed.
This article covers downloading the app, signing in, granting the permissions the app needs, making and receiving calls, and troubleshooting login or no-incoming-call problems.
Download the App
Get The One Voice from your device's app store:
- iOS — the App Store.
- Android — Google Play.
Search for "The One Voice" and install the official app published by The One Stack.
Signing In
The app uses your The One Hub account, so you don't need separate credentials.
- Open the app. You'll see the sign-in screen.
- Tap Sign in with The One Hub. This opens The One Hub in a browser so you can authenticate (including single sign-on, if your organization uses it). After you sign in, the app receives you back automatically and lands you on the keypad.
- If you'd rather sign in directly, tap or sign in directly, enter your email and password, and tap Sign In.
- If your account has multi-factor authentication (MFA) enabled, you'll be prompted to enter your verification code to finish signing in.
- After your first sign-in, the app can offer to enable biometric unlock (Face ID / fingerprint) so you don't have to re-enter your password each time you open it.
If you've forgotten your password, tap Forgot password? on the direct sign-in form.
Granting Permissions
For the app to work as a phone, allow these when prompted:
- Microphone — required for the audio on every call. Without it, calls have no sound.
- Notifications — required so the app can alert you to incoming calls, messages, and voicemail when it isn't open.
On iOS, the app also uses VoIP background capabilities so incoming calls can ring the native call screen even when the app is closed or your phone is locked.
If you tapped "don't allow" by mistake, you can grant these later in your device's Settings under The One Voice. The app won't keep nagging you, but calls and call notifications won't work fully until microphone and notification access are granted.
Making Calls
- Open the Keypad tab.
- Dial a number, or pick a contact, and tap to call.
- The active-call screen gives you mute, hold, speaker / audio-output selection, keypad (for DTMF tones), and transfer.
You can also call back from the Recents tab or place a call from a Contacts entry.
Receiving Calls
When someone calls your business number, the app rings using your phone's native incoming-call screen:
- iOS uses CallKit, so an incoming Voice call looks and behaves like a regular phone call — it rings on the lock screen, and you answer or decline with the standard call controls. This works even if the app was closed.
- Android shows a high-priority incoming-call notification with answer/decline.
Answering from the native screen connects you straight into the call. Mute, hold, and hang-up from the native controls are wired through to the call, so you can manage the call without opening the app first.
Push Notifications and CallKit
So that calls reach you when the app is backgrounded or closed, the app registers for push notifications after you sign in. On iOS it additionally registers a VoIP push token, which lets an incoming call wake the device and present CallKit before the app has even finished loading. You don't configure any of this — it happens automatically once you've signed in and granted notification permission.
Troubleshooting
I can't sign in:
- Double-check your email and password, and confirm you can sign in to The One Hub in a normal browser with the same credentials.
- If you use SSO, use the Sign in with The One Hub button rather than direct sign-in, and complete the browser sign-in fully so it returns you to the app.
- If MFA is enabled, make sure you're entering a current verification code.
Calls have no audio / the other side can't hear me:
- Grant microphone access to The One Voice in your device Settings, then restart the app.
I'm not getting incoming calls:
- Grant notification access in your device Settings.
- On iOS, make sure The One Voice is allowed to use notifications and that Focus / Do Not Disturb isn't silencing it.
- Make sure you're signed in — push tokens are registered after sign-in, so a signed-out app can't receive call pushes.
- Confirm your extension is set to receive calls (see Receiving Calls) and that you don't have Do Not Disturb enabled in Voice.
- Fully close and reopen the app to re-register for push, then place a test call to yourself.
The app keeps asking me to sign in:
- Enable biometric unlock when prompted so the app can keep your session. If sign-in still doesn't stick, sign out fully and sign back in with Sign in with The One Hub.
FAQ
Do I need a separate password for the app? No. The app uses your The One Hub account and supports your organization's single sign-on.
Will it ring when the app is closed? Yes. With notification permission granted, incoming calls ring the native call screen even when the app is closed — on iOS via CallKit and VoIP push, on Android via a high-priority call notification.
Does it use my cellular minutes? No. Calls go over data (Wi-Fi or cellular data) as VoIP, not over your carrier's voice minutes.
Can I use the same account on the mobile app and the web app at the same time? Yes. Your extension can be reached on the mobile app, the web app, and any registered desk phone.