Bitdefender VPN drops overnight on Pixel 9 & PC simultaneously, laptop kill switch fails – Not a standard network drop

Question

Hello Bitdefender Community,

​I am experiencing a highly unusual, persistent security issue across my devices, and I've run out of standard technical troubleshooting options. I am hoping someone here or a Bitdefender engineer might have insight into what is causing this.

​The Setup:

​Primary Device: Google Pixel 9 acting as a mobile hotspot.

​Secondary Device: Windows Laptop connected to the Pixel 9 hotspot.

​Security Suite: Bitdefender Premium / Total Security with Bitdefender VPN active on both devices.

​Environment: International travel (relying entirely on mobile cellular data via the hotspot).

​Settings: Automatic app/OS updates are completely disabled on both devices.

​The Problem:

​For multiple nights now, while I am asleep, both the Pixel 9's VPN and the laptop's VPN are completely and silently dropping at the exact same time.

​Crucially, the laptop's VPN Kill Switch is failing completely. When the tunnel drops, the laptop remains fully connected to the unencrypted internet rather than blocking traffic. By morning, both devices are completely exposed.

​What We Have Checked & Ruled Out:

​We have systematically eliminated the standard culprits using device logs and security dashboards:

​Not a Standard Carrier Disconnect/IP Reset: This is happening consistently, whereas routine carrier IP lease drops have never killed the VPN tunnels entirely in the past.

​Not an App/OS Update: Automatic updates are locked down and off.

​Not a Server-Side Session Ban / Account Lockout: I checked the Bitdefender Central dashboard notifications and activity logs immediately after an incident. There are zero alerts, no "session limit exceeded" flags, and no suspicious activity warnings from the night before.

​Not Thermal Throttling / Hardware Protection: I audited the Pixel 9's Android battery usage logs (Battery -> Battery usage). The charging and battery level line is perfectly smooth, flat, and sitting near 100% all night. There are no jagged dips, charging pauses, or hardware power-saving kills that would indicate the phone overheated from running the hotspot.

​No Unauthorized Wi-Fi Connections: I have closely monitored the hotspot management interface on the Pixel 9. No second or unauthorized device has ever connected to the Wi-Fi network; only my laptop is registered.

​Password Resets Didn't Kill Persistent Tunnels: I updated passwords across my accounts, Killed all connections in Bitdefender reinstalled all software for Bitdefender signed in with new passwords, and the issue repeated the following night.

​Current Status:

​Because the laptop's Service Control Manager shows aggressive, rapid-fire network driver and service looping when idle, and because the phone's VPN turns off cleanly with zero crash logs or server alerts, it behaves as if an external factor or a deep local conflict is intentionally dropping the security layers.

​I have recently enabled Android's system-level Always-on VPN and Block connections without VPN to force the phone's kernel to drop the connection if Bitdefender fails tonight, and I have refreshed the hotspot credentials.

​My Questions for the Community:

​Has anyone seen a scenario where a Windows driver/service loop on a connected client can trigger a clean, silent shutdown of the Bitdefender VPN app on the host Android device?

​Why would the Windows Bitdefender Kill Switch fail to drop the network gate when a connection failure occurs overnight?

​Are there specific low-level Bitdefender log files (outside of the standard Central Dashboard notifications) that I can pull from Windows or Android to see the exact hook or command that is terminating these secure tunnels?

​Any advice, advanced logging steps, or architectural insights would be greatly appreciated. Thank you!

Alexandru_BD · Answer

Thanks for the clarification. I understand why the timing of the drops is concerning, especially when you are relying on mobile data while traveling. That said, based on what you’ve described so far, I would not jump directly to a coordinated attack conclusion yet. There are still several more likely causes to isolate first, for example Android hotspot/VPN routing behavior, Android background restrictions, cellular idle/session renewal, Windows network adapter resets, or a VPN Kill-switch malfunction. So I think you should focus on these first.

For the next test, I would suggest simplifying the setup overnight so you can isolate the failing layer.

Keep Bitdefender VPN enabled only on the Windows laptop, not on the phone, and leave the Pixel only as a hotspot.

On Windows, make sure Bitdefender VPN is fully updated, Kill Switch is enabled, and no other VPN, proxy, network filter, firewall tool, or privacy app is active.

Disable Windows sleep/hibernate/network adapter power saving for the test night, go to Device Manager → Network adapters → Wi-Fi adapter → Power Management → uncheck “Allow the computer to turn off this device to save power”

Windows Settings → Power → prevent sleep while plugged in.

Test the Kill Switch manually before leaving it overnight, so connect the Bitdefender VPN, start a continuous ping or browser session, then disconnect the VPN from inside the app and confirm whether traffic is actually blocked.

If the Kill Switch does not block traffic during a manual disconnect, that should be treated as the main issue and escalated to Bitdefender Support with logs. But we'll get to that.

On the Pixel, exclude Bitdefender VPN from battery optimization and check whether Android is allowed to pause or restrict the app in the background, as recommended in the previous article I've shared.

Try a different VPN protocol and server in Bitdefender VPN, and avoid automatic server selection just for the test.

If possible, run one night using a different network source, such as hotel Wi-Fi or another hotspot, to see whether the drop follows the carrier/hotspot or follows the device/VPN installation.

For logs and Support escalation, the most useful items would be:

* Exact timestamp when the VPN dropped.
* Windows Event Viewer logs around that time, especially System logs for WLAN-AutoConfig, RasClient, DNS
* Client, NDIS, network adapter resets, sleep/resume, and Bitdefender-related services.
* Bitdefender Support Tool logs from the Windows laptop.
* Android bug report/logs from the Pixel shortly after reproducing the issue.
* Confirmation whether the Windows Kill Switch fails during a manual VPN disconnect, or only during the overnight drop.

If the Windows Kill Switch fails in a manual test, I’d recommend opening a ticket with Bitdefender Support rather than continuing here, because that needs product-side investigation.

I hope this helps.

Wonderzz · Answer

So this is my understanding running a VPN on the phone and the laptop

The Phone Splits the Network in Two

​Your phone handles your regular phone apps and your hotspot as two completely separate networks:​The Phone's Personal Data: This goes through your phone's internal network card, where your mobile VPN app sits and encrypts everything.

​The Hotspot Network: When you turn on your hotspot, your phone acts exactly like a regular physical internet router. It takes the raw, unencrypted internet data coming from your computer and passes it straight out to the cellular network, completely bypassing the VPN app running on the phone.

My core concern right now is that the VPN kill switch is completely failing on Windows. On top of that, on my Pixel, the VPN keeps turning off entirely—almost like someone is physically closing out the app. The way both devices are failing at the same time makes it feel less like a random glitch and more like a coordinated attack on my connection security.

I was able to find a setting on my phone that shuts down all data without a VPN but it doesn't stop the separate hotspot from transmission as stated above

Alexandru_BD · Answer

Hello,

May I ask why run the VPN on both devices? If the hotspot has a VPN, then all connected devices will benefit from an encrypted connection. Sure, if the VPN disconnects on the mobile device, then this would leave internet traffic exposed on all devices connected to that hotspot, but here the Kill-switch feature SHOULD normally kick in. Also, there COULD be a conflict when using two VPNs, even if they come from the same provider. More details below.

There's an article that dives into the possible reasons why the VPN may disconnect on Android and you can check it out here:

https://www.bitdefender.com/consumer/support/answer/2099/

Try the steps from the article and connect one VPN at the time, so for example test without the VPN enabled on the PC in this case, only on the mobile hotspot. Another thing to keep in mind is that the VPN also displays a "keep-alive" notification on long connections, so perhaps if this notification pops-up at night while the VPN is connected and there's no user input, this could automatically disconnect the VPN? It's a hypothesis, since I'm not 100% sure that's the correct flow. Anyway, retest after applying the recommendations from the above article and use a single VPN connection, then see what happens.

Going forward, given your specific setup and circumstances, if nothing here helps, you can get in touch with Bitdefender Support and they can perform further checks on their end and advise accordingly. Should you require their expertise, you can contact them using the link below:

https://www.bitdefender.com/consumer/support/help/

State your contact reason, choose request category, then select from the available contact channels, chat, phone and email/ticket. Chat would be the fastest way to reach them.

Let us know how it goes.