ESXi 5.5 Error: vSphere Client could not connect

Can’t connect to one virtual host with vsphere, but the others are working from the same client.

vSphere Client could not connect to “192.168.1.100”.
An unknown connection error occurred. (The client could not send a complete request to the server. (The underlying connection was closed: An unexpected error occurred on a send.))

http://tsmith.co/2013/xp-cant-connect-via-vsphere-5-5-c-client/

The solution:
So, how do we get around this? Well, the best answer would be to upgrade to Vista or higher. Obviously, if you haven’t yet, there is a reason.
On 64bit version of XP and 2003, simply install this hotfix from Microsoft. If you are using a 32bit version, there is no hotfix, and we need to edit the vCenter server to allow older encryption methods.

Fortunately (if SSH is enabled), richardvm over on this post on the VMWare forums has instructions for handling it;

4. Re: Windows XP vSphere Client 5.5
For those that don’t have vCenter or want to connect to a stand alone ESXi 5.5 host via the vSphere Client, you’ll need to ssh into the ESXi host and modify the following file: /etc/vmware/rhttpproxy/config.xml

Insert the following xml line into the appropriate section:

<vmacore>
        ...
        <ssl>
            ...
            <cipherList>ALL</cipherList>
        ... 
        </ssl>>
    ...
</vmacore>

After saving your changes restart the service:
/etc/init.d/rhttpproxy restart