Connect to Outlook is installed, but not appearing in the Toolbar (Ribbon)

Behavior: 
When you open Outlook, the Connect to Outlook plugin does not appear on the Toolbar (Ribbon)

Solution:
To troubleshoot this issue, please try the following,

1. Verify that they’re using a Supported version of Outlook.
   7.0 – Outlook 2013 (x32 & x64) / Outlook 2016 (x32 & x64)
   7.1 – Outlook 2013 (x32 & x64) / Outlook 2016 (x32 & x64)
   7.2 – Outlook 2013 (x32 & x64) / Outlook 2016 (x32 & x64)
   7.3 – Outlook 2013 (x32 & x64) / Outlook 2016 (x32 & x64) / Outlook 2019 (x32 & x64)
   7.4 – Outlook 2013 (x32 & x64) / Outlook 2016 (x32 & x64) / Outlook 2019 (x32 & x64)
   7.5 – Outlook 2013 (x32 & x64) / Outlook 2016 (x32 & x64) / Outlook 2019 (x32 & x64)
   7.6 – Outlook 2013 (x32 & x64) / Outlook 2016 (x32 & x64) / Outlook 2019 (x32 & x64)
   7.7 – Outlook 2013 (x32 & x64) / Outlook 2016 (x32 & x64) / Outlook 2019 (x32 & x64)
   7.8 – Outlook 2013 (x32 & x64) / Outlook 2016 (x32 & x64) / Outlook 2019 (x32 & x64)
   7.9 – Outlook 2013 (x32 & x64) / Outlook 2016 (x32 & x64) / Outlook 2019 (x32 & x64)
   7.10 – Outlook 2016 (x32 & x64) / Outlook 2019 (x32 & x64) / Outlook 2021 (x32 & x64)
   7.11 – Outlook 2016 (x32 & x64) / Outlook 2019 (x32 & x64) / Outlook 2021 (x32 & x64)
    
2. Verify that Connect to Outlook is installed via Programs & Features for DocuWare versions 7.3 and below or the Client Setup Installer for versions 7.4 and above. 
   If it’s installed, please refer to step 3.
   If it’s not installed, please install it via the Desktop Apps installer.
    
3. Verify that Connect to Outlook is present in Outlook Add-Ins.
   File > Options > Add-Ins > Check Active & Disabled Add-Ins. Sometimes a dependency gets disabled (adxloader), which can cause this issue.
    
4. Verify that AntiVirus is not an issue.
    
5. Navigate to Outlook using Command Prompt (C:\Program Files (x86)\Microsoft Office\root\Office16\Outlook.exe). Run the command Outlook.exe /cleanviews

If you are still experiencing issues after performing the above steps, please open Outlook by clicking “Run as Administrator”
If the Add-In appears when this is done, please exit Outlook and then do the following,

1. Grant full rights on “C:\Windows” to the user experiencing the issue.
2. If that did not work, then please check the following folders:
   C:\Windows\assembly\GAC_MSIL\office
   C:\Windows\assembly\GAC_MSIL\Microsoft.Vbe.Interop
   C:\Windows\assembly\GAC_MSIL\Microsoft.Office.Interop.Outlook
   
   All of these folders are normally one or two folders with this name 15.0.0.0__71e9bce111e9429c or 14.0.0.0__71e9bce111e9429c.
   If you open the folders, the dll files will be there.
   Right-click  go to properties and choose the ribbon “Details” for each dll file
   If the Details are not filled in or some fields are empty, then the dll is not registered.
   You can register the dll with the following:
   
   Move the dll from the folder to the desktop and then back to the folder. Please check if the fields from the details ribbon is filled in or not.
   If they are filled, please do the same for the other dll's