I have a question regarding RealVNC and the Raspberry Pi 3B. I can't connect to the Raspberry pi and I get following error message: "Timeout while waiting for a response from the computer". A VNC connection worked fine a few months ago, but now I somehow just can't connect to the RPi.

What I have tried so far:

  • Reboot of Computer (Client) and RPi (Server)
  • Reinstalled RealVNC software on both Computer and RPi
  • Checked open ports of RPi: Works fine, 5900 is open
  • Tried VNC Connect on other device (smartphone), but same error message

Everything I checked is working fine, but I still get the error message. And as I said, it worked really good a few months ago and I haven't changed anything regarding the VNC server.

I would be very happy if someone knew a solution for my problem. Thanks already!

  • Are the two computers (client and pi) in the same network? Does ping work?
    – PMF
    Mar 23, 2021 at 13:13
  • I just found the problem. Ufw was active and didn't allow port 5900. Should I delete the question? The only thing I don't understand is why it worked a few months ago, because I used ufw and still could connect. But now it's working again as I added the rule.
    – JacobSelt
    Mar 23, 2021 at 13:18
  • You can add this as an answer. Maybe someone else will have a similar issue.
    – PMF
    Mar 23, 2021 at 13:24

2 Answers 2


Be aware of a few things that could impact this:

Do not open your router firewall to allow VNC from the Internet. It is better for LAN security to create a free account (non-commercial use only) and sign in over the web connect feature provided by RealVNC free of charge.

UFW should restrict the port access to a specific network (your local LAN) or even better a given IP address.

Port 5900 is the default, it can be changed at the Pi end.

A second display uses port 5901, the third 5902 etc


I could not connect because ufw was active and there was no rule for port 5900. So I created a rule and now it works.

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