When Outlook is starting and the Connect to Outlook Add-In is being loaded the following message is shown:
"AddinExpress.MAPI.ADXMAPIStoreAccessor error: the add-in has fired an exception"

Select the option Mail (32 Bit) in the control panel to open the following window:

Select "Show Profiles" to get to the option to create a new profile:

Create a new profile using the "Add"-Button. This will need to be done for all users getting the error message.
After creating a new profile you have to add the email accounts from the user to this new profile and also select the profile from the drop down menu for the option "Always use this profile" (please see screenshot above.)