You add a US number, someone calls it, and your phone stays silent. Almost always, the number is fine and a phone setting is in the way. This guide explains how a call reaches you, then gives the fixes in the order that solves most problems. For the overall picture, see how the TripoSIM number works.

How does a call reach the app?

The TripoSIM US Virtual Number is not on a SIM card. When someone dials it:

  1. The phone network routes the call to TripoSIM.
  2. TripoSIM sends a push notification to your phone over the internet.
  3. Your phone wakes the app, and it rings.
  4. If the app cannot be reached, the caller goes to voicemail.

So three things must work: your internet connection, the push notification, and the app’s permission to ring and use the microphone. Every fix below targets one of those. Texts from US and Canadian senders arrive the same way.

Are notifications and the microphone allowed?

This fixes most silent calls.

  • Notifications on. Allow notifications for the TripoSIM app, including sounds and banners. TripoSIM says calls ring even when the app is closed once notifications and the microphone are allowed; a phone that is off, offline or has notifications blocked does not ring, and callers reach voicemail.
  • Microphone allowed. Without it, calls may ring but you cannot be heard.
  • Signed in. Open the app and check your number shows on the home screen.

Make a test call from another phone after any change.

What should iPhone users check?

On iPhone, add the TripoSIM web app to your Home Screen. Then:

  • Open it from the Home Screen icon, not from a Safari tab. Notifications only work for the Home Screen app.
  • Allow notifications when asked. If you said no, go to Settings, then Notifications, find the TripoSIM app and turn them on.
  • Check Focus. Do Not Disturb, Sleep and Work Focus modes can silence the app. In Settings, then Focus, add the TripoSIM app to the allowed apps for each Focus you use. Apple explains this in its Focus guide.
  • Watch Low Power Mode. It cuts background activity and can delay notifications. Turn it off when you expect calls, or charge before the call. See Apple’s Low Power Mode page.
  • Keep iOS up to date. Web app notifications rely on recent iOS versions.

What should Android users check?

On Android, install the TripoSIM app. Then:

  • Turn off battery optimisation for the app. Go to Settings, then Apps, then the TripoSIM app, then Battery, and choose “Unrestricted” or “Don’t optimise”. Android puts idle apps to sleep to save power, which Google describes in its Doze guide.
  • Check the phone maker’s own saver. Samsung, Xiaomi, Huawei and others add extra battery tools. Look for “sleeping apps”, “auto-launch” or “background activity” and allow the TripoSIM app.
  • Allow notifications for the app, including the call notification category.
  • Do not swipe the app away from recent apps if your phone stops it ringing after you do.

Is your connection good enough?

Calls need a steady connection more than a fast one.

  • Wi-Fi vs data. Hotel and café Wi-Fi often drops calls or blocks call traffic. If calls fail on Wi-Fi, switch to mobile data and test again. A local SIM or a travel eSIM for data works fine.
  • Switching networks. Walking out of Wi-Fi range mid-call can drop it. Stay on one network for long calls.
  • Data saver. Turn off data saver for the app, or it may not get updates in the background.

Could a VPN be the problem?

Yes. A VPN adds a hop between your phone and TripoSIM. It can delay the push notification, so the call stops before your phone rings, and it can break call audio. If calls are unreliable, try with the VPN turned off. We do not recommend using a VPN to get around local rules.

Does your country restrict internet calling?

Some countries block or limit internet calls, and the number may not ring there over local networks even with perfect settings. The rules change, and some only allow licensed apps. Our country table lists the restrictions we have found a source for; wherever you are, check local rules before you rely on the number for calls.

What happens to calls you miss?

They go to voicemail. Messages can be up to 2 minutes long, up to 30 a month, and are kept 30 days. Record a greeting so callers know they reached you. If you know you will be offline, for example on a flight, voicemail is your safety net. Our voicemail guide shows how to set it up.

Incoming calls have a fair use of 300 minutes a month; above that, callers go to voicemail until your minutes reset.

A two-minute checklist

  • Notifications and microphone allowed.
  • iPhone: opened from the Home Screen icon; app allowed in every Focus; Low Power Mode off when you expect calls.
  • Android: battery set to “Unrestricted”; maker’s saver allows the app.
  • Steady connection; VPN off when testing.
  • Voicemail greeting recorded.
  • Test call from another phone.

The number cannot call emergency services, so keep a local mobile line for that.