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VNC Connect error messages

If the recommended resolution does not fix your problem, or if you cannot find your error message, please contact support.

Connectivity error messages

VNC Viewer may display the following error messages if a connection attempt to VNC Server running on a remote computer fails.

Error message This may occur because... Resolution

VNC Server is not currently listening for cloud connections

RealVNC services cannot establish a connection between your device and the remote computer. The resolution depends on the precise cause. Please work through this checklist.

Either the username was not recognised or the password was incorrect

You have not provided the authentication credentials that VNC Server is expecting.

If you have a Professional or Enterprise subscription, enter the user name and password you normally use to log in to your user account on the remote computer.

If you have a Home subscription, enter the password specified when VNC Server was installed.

The user name you have entered does not identify the domain. Prefix the user name with a domain name, for example DEV.ACMECORP.COM\johndoe
The remote computer is running Windows and its Event Log is full. On the remote computer, type eventvwr into the Start menu and then select Windows Logs > Application > Clear Log. Finally, select Properties > Overwrite events as needed.
TeamViewer remote access software is running on the remote computer, which causes a conflict. Either uninstall TeamViewer, close it, or ensure it is not running in ‘unattended access’ mode.

Too many security failures

You have entered incorrect authentication credentials too many times. Wait for the number of seconds specified by the VNC Server BlacklistTimeout parameter (10 by default), and then enter the correct authentication credentials.

Connection rejected by VNC Server computer user

VNC Server is configured to require the local user to manually accept or reject connections, and you have either been rejected or that user is not there.

Ensure the local user is present and accepts your connection.

On the remote computer, you can turn this feature off by configuring the VNC Server QueryConnect parameter, or the Permissions parameter to automatically accept your connections.

The connection closed unexpectedly

VNC Server is blocking your connection attempt. On the remote computer, ensure the VNC Server Hosts parameter is not blocking your computer’s IP address.
VNC Server’s private key is missing or corrupt.

You should investigate why this has occurred. On a remote Mac or Linux computer, note the location of the private key is determined by the VNC Server RsaPrivateKeyFile parameter.

You can restart VNC Server to regenerate the private key, or alternatively at the command line without restarting by running <server-binary> -service -generatekeys.

The remote computer is running Windows and its Event Log is full. On the remote computer, type eventvwr into the Start menu and then select Windows Logs > Application > Clear Log. Finally, select Properties > Overwrite events as needed.

Connection reset by peer (10054)

Your network hardware is misconfigured or faulty (this error is not specific to VNC). Run the command ping -t -l 1350 <remote-ip> to confirm the two computers can communicate with one another, without packet loss.
Your network’s MTU has changed from the default (1500 bytes). It may have been configured manually (usually within router settings), or because you are connecting over a VPN. Using fixed IP addresses rather than DHCP-assigned addresses in your router settings has been known to resolve this issue.
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