Unable to connect to VNC Server using your chosen security setting is a common error that triggers while webmasters connect to VNC Server from VNC Viewer.
This issue happens when VNC Viewer and VNC Server have incompatible encryption settings for a direct connection.
Here at Ibmi Media, as part of our Server Management Services, we regularly help our Customers to resolve related VNC errors.

Causes for unable to connect to VNC Server using your chosen security setting

Often while connecting to VNC Server from VNC Viewer an error message as shown below triggers:

No Matching Security Types

Basically, this error is mainly due to the following reasons:

1. Incompatible encryption settings for a direct connection between VNC Viewer and VNC Server.
2. Legacy VNC server running on the remote computer or third-party VNC-compatible software that does not support encryption.

How to fix unable to connect to VNC Server using your chosen security setting ?

As mentioned earlier, this error generally happens due to incompatible encryption settings between VNC Viewer and VNC Server.
To try to fix this error is to change the VNC Server Encryption parameter to something other than AlwaysOff on the remote computer.
Then, they try to change the VNC Viewer Encryption parameter to Server, PreferOn or PreferOff.
As the alternate cause for this error would be the version of the VNC server, they also ensure that the latest version of VNC Connect is installed on the remote computer.
If not, they upgrade VNC Server to a more recent version.
A not much-recommended method to fix the error is to weaker the level of encryption.

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