Signal calls not working? Diagnose and fix in the right order

Published: October 7, 2026 · Updated: October 8, 2026

Most Signal call failures come from one of four layers: missing permissions, a blocked network, a battery manager killing the app, or a strict network that needs relay mode. Check them in that order, permissions first, then network, then battery, then relay, and you will find the cause without wasting time on random fixes. This guide covers calls that won't connect, incoming calls that never ring, and calls that drop immediately, on any Android phone running the official Signal build (Play Store or the website APK, current version 8.29.3).

Match your symptom to the cause

Work the layers in order even if you think you know the answer. Call problems often have two stacked causes, for example, a VPN that blocks the connection and a battery manager that kills incoming-call signaling.

Layer 1: permissions

Signal needs three permissions to handle calls. If any is denied, calls fail in confusing ways, sometimes silently:

1. Open Signal's app permissions

   Go to Settings → Apps → Signal → Permissions. This one screen shows everything Signal is allowed or denied.

2. Allow Microphone

   Set Microphone to Allow (or "Allow only while using the app"). Without it, you can hear the other person but they hear nothing from you, and on some phones the call won't start at all.

3. Allow Camera

   Set Camera to Allow. Voice calls technically need only the mic, but video calls and call-preview features need the camera permission too.

4. Allow Notifications

   Set Notifications to allowed, with the call notification category enabled. On some phones, denied notifications = incoming calls that never ring. Our master notification guide covers this in depth.

5. Check "Nearby devices" if shown

   On Android 12 and newer, Signal may request Nearby devices for Bluetooth audio. If you use Bluetooth headsets for calls, allow it, otherwise call audio may refuse to route to the headset.

Layer 2: network

Signal calls are real-time voice/video over the internet. They need a stable connection with low latency, and some networks actively block the traffic:

1. Test both Wi-Fi and mobile data

   Switch networks and try a call. If calls work on mobile data but fail on Wi-Fi, the Wi-Fi network (office, school, hotel, some ISPs) is blocking or throttling call traffic. If both fail, keep going, the problem is on your phone.

2. Turn off the VPN temporarily

   VPNs reroute all traffic and many of them break real-time call connections, add latency, or get blocked by Signal's servers. Disable the VPN and test. If calls start working, the VPN is the cause, try a different server or split-tunneling that excludes Signal, if your VPN app supports it.

3. Check data saver and private DNS

   Data saver (Settings → Network → Data saver) can throttle background and real-time traffic, add Signal to its unrestricted list. Private DNS set to a strict filtering provider can break connections; test with it off.

4. Rule out the other person's network

   Call a second contact. If calls to one person always fail but others work, the problem is on their end, their permissions, their network, or their battery manager. This simple test saves hours of fixing the wrong phone.

Layer 3: battery and background killing

Incoming calls arrive through the same background connection as message notifications. If your phone kills Signal in the background, incoming calls never ring, you'll just find a "missed call" later, or nothing at all.

1. Exempt Signal from battery optimization

   Go to Settings → Apps → Signal → Battery and set it to Unrestricted (or "Don't optimize"). This is the baseline fix on every brand.

2. Apply your brand's full exemptions

   Samsung, Xiaomi, Huawei and BBK brands (Oppo/Vivo/Realme/OnePlus) each add their own killing layers on top of stock Android. Use the matching guide: Samsung, Huawei, Oppo/Vivo/Realme/OnePlus. The notification guides fix calls too, because it's the same background connection.

3. Don't swipe Signal away before expecting a call

   Swiping Signal out of recents force-stops it on many phones. If you're waiting for an important call, leave Signal running.

Layer 4: relay mode for strict networks

By default, Signal tries to connect calls directly between the two phones (peer-to-peer). Some networks, corporate firewalls, school Wi-Fi, hotel networks, some mobile carriers, block direct connections. When that happens, calls fail even though everything else works.

1. Open Signal's call settings

   In Signal, go to Settings → Privacy → Advanced (the exact location can move between versions, look under Privacy settings).

2. Enable "Always relay calls"

   Turn on Always relay calls. This routes every call through Signal's servers instead of connecting directly. It works around firewalls and NAT restrictions that block peer-to-peer traffic.

3. Know the trade-off

   Relayed calls hide your IP address from the other person (a privacy win), but the extra hop can add slight latency. On a normal home network, leave it off for the best quality; on a strict network, turn it on to get calls working at all.

If calls work everywhere except one specific Wi-Fi network, that network is the problem, relay mode is the fix, and it's also worth asking the network admin whether VoIP traffic is blocked.

Special cases

• Bluetooth headset problems: if call audio won't route to your headset, or the headset mic doesn't work, allow the Nearby devices permission (Android 12+) and re-pair the headset. Some headsets also need their own app's permissions to function as a call device.
• Group calls failing: group calls route through Signal's servers and need more bandwidth per participant. If one-to-one calls work but group calls don't, suspect bandwidth, our call-quality guide has the details.
• Do Not Disturb: check for forgotten DND schedules, incoming calls are silenced just like notifications.
• Call screening / spam blocking: some phones' dialer apps or carrier spam filters interfere with VoIP call signaling. If calls from one specific number always fail, check the phone app's blocked/spam list.
• Low storage: a phone with nearly full storage misbehaves in strange ways, including failed calls. Free up space if you're under ~1 GB free.

Last resorts

If all four layers check out and calls still fail:

1. Update Signal

   Check signal.org/android/apk for the latest website build (currently 8.29.3). The website build updates itself, but if updates stalled, grab it manually. Call bugs do get fixed in updates.

2. Restart the phone

   A plain reboot clears stuck audio services and network states. It's boring and it works more often than it should.

3. Reinstall as the final option

   Back up your chats first (Signal → Settings → Chats → Chat backups), then uninstall and reinstall. This fixes corrupted installs but wipes local data, which is why it's last, not first.

Frequently asked questions

Related: fixing microphone problems on calls, improving choppy call quality, master notification diagnosis, and the troubleshooting hub.