This error can occur that after logging in to your Engage Client/Vixie/Encompass LT, you see the following message.

This is currently caused by some old settings carrying over from release 55 to 56. 

The quickest way to resolve is by selecting your practice in your account settings.

To do this, access your account settings by left clicking on Your Name in the top right hand corner of Vixie.

This link will take you into your account settings, once on this page, scroll to the very bottom of the screen where you'll see, 

Organisations that you are a member of

Usually there will only be one site in the list, simply left click to select it and you'll be taken straight to your messages.

(where there are multiple sites, simply select the site you wish to see messages for.)

If there are no sites listed in this section, please choose Logout from the top right corner and log back in once more. This should then show the organisation.