If the app just opens to a blank screen or a generic login that won't work, you need to clear the local app data.
<ol data-path-to-node="4" start="1">
<li>
Fully Close MiCollab: Right-click the MiCollab icon in your system tray (near the clock) and select Exit.
</li>
<li>
Clear AppData:
<ul data-path-to-node="4,1,1">
<li>
Press <code data-index-in-node="6" data-path-to-node="4,1,1,0,0">Windows Key + R</code> on your keyboard.
</li>
<li>
Type <code data-index-in-node="5" data-path-to-node="4,1,1,1,0">%appdata%</code> and hit Enter.
</li>
<li>
Locate the Mitel or MiCollab folder.
</li>
<li>
Delete the folder named <code data-index-in-node="24" data-path-to-node="4,1,1,3,0">MiCollab</code>. (This won't uninstall the program, but it will wipe the "memory" of any previous setup).
</li>
</ul>
</li>
<li>
Relaunch: Open MiCollab again. It should now treat you as a brand-new user and ask for your Authentication Key or Server FQDN.
</li>
</ol>

If the app just opens to a blank screen or a generic login that won't work, you need to clear the local app data.

 1. Fully Close MiCollab: Right-click the MiCollab icon in your system tray (near the clock) and select Exit.

 2. Clear AppData:
    
    * Press Windows Key + R on your keyboard.
    
    * Type %appdata% and hit Enter.
    
    * Locate the Mitel or MiCollab folder.
    
    * Delete the folder named MiCollab. (This won't uninstall the program, but it will wipe the "memory" of any previous setup).

 3. Relaunch: Open MiCollab again. It should now treat you as a brand-new user and ask for your Authentication Key or Server FQDN.

MiCollab won't start or prompt for authentication key

Access MiTel Voicemail