contentACCESS Outlook add-in certificate issue
PROBLEM:
contentACCESS Outlook (VSTO) add-in does not work because of certificate issue.

Screenshot.1. Outlook add-in error
SOLUTION:
It means that Outlook is not able to load the add-in correctly because of certificate signature algorithm. Our contentACCESS Outlook add-in supports SHA2 signature. It can cause problems when using with older Outlook clients.
The following should be present on client machine(s) where add-in is installed:
- .NET 4.8
- Visual Studio 2010 Tools for Office Runtime 10.0.60724 (can be downloaded here)
This thread will also help you with solving the issue.