When Signal notifications stop working, the cause is usually not the message itself. The break is often somewhere in a chain: network access, app-level preferences, operating-system permissions, battery controls, Focus or Do Not Disturb, or a desktop setting. Checking that chain in order is faster and safer than reinstalling immediately.
This guide covers Android, iPhone, Windows, and Mac while keeping privacy in view. It focuses on missed or delayed alerts, silent notifications, and cases where messages appear only after Signal is opened. For general privacy settings, account credentials, and linked-device practices, see the site's Signal guides. signalim.net is an independent guide and does not operate Signal accounts or message services.
1. Identify the exact symptom first
Before changing settings, ask a trusted contact to send one test message while Signal is closed and the screen is locked. Record what happens:
- No alert appears, but the message is waiting when the app opens.
- A banner appears with no sound or vibration.
- Only one conversation or group is silent.
- Mobile alerts work, but desktop alerts do not.
- Alerts fail only on Wi-Fi, cellular data, a work network, or a VPN.
- The notification appears but reveals more sender or message information than you want.
These symptoms point to different layers. One silent group suggests a conversation mute; failure only while the phone sleeps suggests background or battery restrictions; failure only on a corporate network suggests a firewall or proxy issue.
2. Run the universal five-minute check
- Confirm internet access. Toggle airplane mode off and on, then test Wi-Fi and cellular data separately.
- Update Signal and the operating system. Use the official app store or authorized desktop source described in the download guide.
- Check the conversation. Make sure the contact is not blocked and the chat or group is not muted.
- Check Signal's notification preference. Open Signal Settings > Notifications and confirm alerts and sounds are enabled.
- Check system notification permission. The operating system can override the setting inside Signal.
If the test now works, stop changing settings. If it still fails, follow the platform section below. Avoid uninstalling as a first troubleshooting step because message history may depend on a prepared backup or transfer method.
3. Android: check background delivery before advanced fixes
Android manufacturers add different battery and background controls, so menu names vary. Start with Settings > Apps > Signal and verify:
- Notifications are allowed, including the relevant notification categories.
- Background data is enabled and Data Saver does not restrict Signal.
- Battery use is unrestricted or Signal is excluded from aggressive optimization.
- Background activity and auto-start are allowed if the phone exposes those controls.
- Wi-Fi or mobile data remains available while the phone sleeps.
- Do Not Disturb is not suppressing the alert you are testing.
Then update Google Play services and Android System WebView where they are used by your device. Confirm the phone has free internal storage and that date, time, and time zone are correct. Signal's official troubleshooting page also lists manufacturer-specific controls for Samsung, Xiaomi, Huawei, OnePlus, Oppo, Vivo, and other devices; use those only after the general checks.
A common diagnostic clue is this: if messages arrive immediately when you open Signal but not while it is closed, the app is probably being put to sleep or denied background network access. If failure occurs only on one network, skip ahead to the network section.
4. iPhone: check permission, Focus, power, and push registration
Open iPhone Settings > Apps > Signal > Notifications. Turn on Allow Notifications, then choose the alert surfaces you want, such as Lock Screen, Notification Center, Banners, Sounds, and Badges. Apple may change the path slightly between iOS versions, but Signal must be allowed at the system level.
Next check these items:
- Cellular Data: Signal needs network access when Wi-Fi is unavailable.
- Background App Refresh: allowing background refresh helps timely delivery. Low Power Mode can interfere with it.
- Focus: open Settings > Focus, select the active mode, and allow Signal if that mode should permit its alerts.
- Silent mode and sound: make sure the device is not intentionally silent and Signal Settings > Notifications > Message Sound is configured.
- Conversation state: confirm the sender is not blocked and the thread is not muted.
If permissions look correct but push alerts still fail, Signal's official iOS guidance includes Signal Settings > Notifications > Re-register Push Notifications. Use that built-in command, confirm the prompt, and repeat the locked-screen test.
5. Windows and Mac: separate Signal settings from OS settings
On Signal Desktop, open Settings > Notifications and verify that desktop notifications are enabled and the privacy level is what you expect. Then check Windows Notifications or macOS System Settings > Notifications > Signal. Both layers must permit alerts.
Also confirm that Signal Desktop is still linked and current. If the desktop has already displayed or marked a message as read, the mobile notification behavior may look different from a simple single-device test. Test again with the desktop closed to isolate that variable.
On macOS, Signal notes a specific behavior: disappearing messages can display a generic “New Message” alert regardless of the preview choice in Signal's notification settings. That is a privacy-preserving fallback, not necessarily a notification failure.
6. Network, VPN, firewall, and proxy checks
When notifications work on cellular data but fail on a campus, office, hotel, or filtered Wi-Fi network, the network is the likely boundary. Test another trusted network before changing the account. VPNs, local filtering apps, firewalls, transparent proxies, and reverse proxies can interrupt Signal's persistent connection.
Signal's official Android guidance says filtered networks should allow Signal services and support WebSockets; it lists TCP ports 80, 443, and 31337 and all UDP for relevant configurations. Do not weaken a managed corporate firewall on your own. Give the official requirements to the network administrator, or use a permitted network that already supports the connection.
Correct system time also matters. A badly wrong clock can break secure connections and make alerts appear delayed or out of order. Set date and time automatically, then restart the app and repeat one controlled test.
7. Fix privacy previews without disabling delivery
A working notification does not have to reveal message text. In Signal Settings > Notifications, choose whether alerts show the sender name, sender and message, or a generic new-message notice. Then review lock-screen preview settings in Android or iOS.
For shared workspaces, presentations, and travel, prefer generic previews and lock the device when it is unattended. For an important contact or group, use per-conversation mute and notification settings rather than turning off every alert system-wide.
8. What not to do
- Do not uninstall Signal until you understand how message history is backed up or transferred.
- Do not clear app data as a routine notification fix.
- Do not share SMS codes, PINs, recovery keys, logs containing personal details, or screen-control access with an unknown “support” contact.
- Do not disable every battery or security control on the phone; change only the setting that affects Signal, then retest.
- Do not assume that a visible message after opening the app proves notifications are working in the background.
9. A simple test matrix for persistent problems
Run four tests with one trusted sender: Wi-Fi with the app closed, cellular data with the app closed, the device locked for several minutes, and the linked desktop closed. If only one condition fails, you have narrowed the cause to a network, background restriction, or linked-device interaction. Capture the app version, operating-system version, phone model, failed condition, and approximate time before contacting official support.
For authoritative, frequently updated steps, use Signal Support's notification troubleshooting guide and its permissions and operating-system settings reference. The site's privacy page explains how this independent guide handles browsing data and outbound links.
Reviewed September 9, 2026. Operating-system labels and manufacturer battery controls can change with updates.