Incoming calls on locked vivo V2440 only vibrate briefly and disappear

[Pavel44444]

Steps to reproduce

Describe the bug

On my vivo V2440, incoming calls in Nextcloud Talk are unreliable when the phone is locked.

Symptoms:

• when the phone is unlocked, incoming calls usually work
• when the phone is locked, an incoming call often only vibrates briefly (sometimes 1 short ring / 2 vibrations) and then disappears
• after that, the call cannot be accepted unless I manually unlock the phone, open Talk, and then join if the call is still there
• text message notifications arrive on the locked phone correctly
• another phone with a different account on the same server works fine, so this seems device-specific

Sometimes the first call fails, the next one works, and behavior is inconsistent.
In one test, after about 30 minutes of the phone being locked and untouched, an incoming call only vibrated briefly and then died.

Steps to reproduce

1. Install Nextcloud Talk from Google Play
2. Log in to the server
3. Lock the phone and leave it untouched for some time
4. Start a call to this device from another Talk user
5. Observe the incoming call behavior

Expected behavior

When the phone is locked, an incoming call should ring normally and stay visible long enough to be accepted.

Actual behavior

When the phone is locked, the call often only briefly vibrates/rings and then disappears.

What I already checked

• app installed from Google Play
• Google Play Services available and up to date
• battery optimization ignored
• notification permissions granted
• calls notification channel enabled
• messages notification channel enabled
• autostart enabled
• full-screen notifications enabled
• background power usage allowed
• unrestricted data allowed
• app locked in recents
• antivirus removed for testing
• problem still remains

Server / app environment

• Device: vivo V2440
• Android version: 36
• App version: Nextcloud Talk v24.0.4
• Build flavor: gplay
• Server: https://pavelcloud.dedyn.io
• User: Pavel Poupera
• Server version: 33.0.7
• Server Talk version: 23.0.9
• Signaling mode: External

Diagnosis information

• Google Play services are available
• UnifiedPush services: 0 services available
• Battery optimization is ignored, all fine
• Notifications are granted
• Calls notification channel enabled: Yes
• Messages notification channel enabled: Yes
• Firebase push token: present
• Registered users: 1
• Server notification app installed: Yes
• Server supports webpush: No
• Latest push registration at server: 2026-08-26 07:22:39
• Latest push registration at push proxy: 2026-08-26 07:22:39

Expected behaviour

When the phone is locked, an incoming call should ring normally and stay visible long enough to be accepted.

Actual behaviour

When the phone is locked, the call often only briefly vibrates/rings and then disappears.

Device brand and model

vivo V2440

Android version

16 (API 36)

Nextcloud Talk app version

24.0.4

Nextcloud server version

33.0.7

Talk version

23.0.9

Custom Signaling server configured

Yes (specify version in Additional Information)

Custom TURN server configured

None

Custom STUN server configured

None

Android logs

No response

Server log

Additional information

Using Nextcloud AIO integrated external signaling backend.

[mahibi]

Thank for the detailed report @Pavel44444

another phone with a different account on the same server works fine, so this seems device-specific

That's a good observation. But unfortunately hard to reproduce.
We plan for have a closer look at calls after the next major release, i will keep this issue in mind!

[Pavel44444]

Thank you for your feedback.

I understand that this is probably hard to reproduce.
If needed, I am happy to provide more tests or additional information.

For reference: on the same Nextcloud server, calls are working normally on two other phones. The issue seems to happen only on this vivo device.