Why do I get "The RPC server is unavailable" error when logging in to QuickBooks Desktop?

Overview

When logging into Quickbooks, this error is given:

"Error has occurred [CB-211]

The RPC server is unavailable, [Exception from HRESULT: 0x800706BA]"

Environment

Quickbooks Desktop

Resolution

• The server is unavailable message indicates a temporary loss of connection to the company file.
• Close and reopen Quickbooks to re-establish connection and for AvaTax to restart.
  • If this does not resolve the error, or you cannot find or access your company file, please reach out to Intuit Support
• Once you are able to access the company file, select Edit > Preferences and ensure that "Keep QuickBooks running for quick start-ups" is unchecked.  
  • Completely exit out of QuickBooks. 
    • Once QuickBooks is closed, Start the Windows Task Manager by pressing CTRL+SHIFT+ESC,  or launching from the taskbar menu (right-click the windows task bar and select "Start Task Manager").
      • In the Processes tab ensure that each of the following processes are not running (within the Windows Task Manager):
        • EventCallbackWrapper
        • AvalaraEventCallbackWrapper
        • QBW32,  any other files beginning with "QB", and any Intuit programs
  • Right click on the icon for QuickBooks, select "Run As Administrator". 
    • Log in as Administrator (if possible). 
    • If QuickBooks prompts you to manually navigate to the location of the Company File, do so. 
    • Attempt to enter File > AvaTax > Configuration. 
      • If it works, exit out, run QuickBooks normally.
  • If the previous step does not work, exit the program, and run QuickBooks normally, logging in as Admin once again.
  • Check for multiple versions of AvaTax in the Integrated Applications found in the preferences menu.
  • If these steps do not solve the issue, please submit a case to Support.