If I configure an SSH entry to use tailscale (no matter if manually, automatically or any other way) I am always getting the message in the screenshot or no message at all. As I did not find any documentation about the tailscale feature I am completely stuck. Can you help me here please or point me to the documentation where the use of this feature is described?

Hi,
Did you happen to launch Tailscale at least once before launching your entry? The application usually needs to be opened at least once so it can initialize properly before any integration can use it.
From your description, it sounds like the integration may not be able to detect or communicate with the Tailscale client. I’d recommend confirming that Tailscale is installed in the Application folder, running, and that you’re logged in with an active device.
Unfortunately, there isn’t official documentation available for this feature yet, so ensuring Tailscale itself is fully operational is an important first step.
Also, could you share a bit more about your setup? For example, how you configured your entry, and what environment you’re running this on. That would help narrow things down.
Best regards
Samuel Oliveira Martel