(Bug) New update on Samsung S25 Ultra drops Nebula connections

[mdenuit]

Hello,

Since the latest security upgrade for Samsung phones (especially the S25 Ultra model), the mobile Nebula app cannot connect reliably. It tries to connect with handshakes but timeouts after 3 tries (being on the local Wi-Fi and trying to reach a node on the same local network).

Then it tries to relay but finally the tunnel is 'dead' after 10-30 seconds and there is the error message: "sendNoMetrics failed to find HostInfo" certName=s25-mobile error="unable to find host with relay" localIndex=... relay=10.10.0.1 remoteIndex=... vpnIp=10.0.1.6 "Tunnel status" certName=s25-mobile localIndex=... remoteIndex=... tunnelCheck="map[method:active state:dead]" vpnIp=10.0.1.6

The mobile app was perfectly stable for 2+ years without any issues despite changing networks often and visiting countries, but since the update there has been this bug where the connection works for 10-15 seconds and the tunnel drops dead again.

I tried disabling IPV6 on the router, restarting from zero the mobile app + lighthouse/relay + the node to access but it's still the same issue. All other devices on Windows and Linux work as usual.

The security update should concern June 2025 and the phone now has the version "S93xBXXS4AYF1": https://security.samsungmobile.com/securityUpdate.smsb https://www.sammobile.com/news/galaxy-s25-june-2025-security-update-europe-india/

Thanks for any feedback or ideas on how to fix this, either on the phone or through the Nebula app.

Update: it works on Wi-Fi at another place, I will close if the issue doesn't persist at the old place