Signal app is blocked by Surfshark VPN

Hi
I use a Galaxy S7 edge with eOS 3.0.1/Android 12, Signal messenger 7.45.3 and Surfshark VPN 3.16.2.
Unfortunately this configuration blocks the Signal messenger from sending and receiving messages. I can circumvent this situation by stopping the Surfshark VPN. After having stopped (or paused) the VPN then the Signal messenger works with no problems. At the first sight it seems that Surfshark is the problem.
But: on a different device with Google Android 14 the Signal app works smoothly with Surfshark. So I assume that the root cause for Signal failing on my eOS device is not Surfshark but the eOS combinded with Surfshark. Perhaps there are some ‘advanced privacy’ settings on the eOS that might cause this failure. So I am interested to get a hint how I can use both Signal messenger and (Surfshark) VPN on my eOS device.

Thank you in advance,
Jochen

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