For the addin to work it needs to be able to reach the Microsoft app catalog. If you see this error it means your local Excel application cannot talk with Microsoft servers. Basically, your local machine cannot "talk" to the app catalog for some reason. There can be several reasons why this happens:
- No internet connection
- Blocked by your firewall
- Access has been disabled by your company security policy
- Add-in installation has been disabled by your Microsoft Office administrator
These issues are outside of the support that Inflectra can provide its customers. Please seek the help of your IT team or admins to help you.