Hello,
My company is wanting to use the Outlook Add-in. We are using the the April 2019 build 14.0.29530.0 version. I'm currently trying to test this out on a test instance using a self-signed certificate (won't do this for production).
After creating the self-signed cert I applied the certificate thumbprint to the test instance under "General". This allowed me to install the "Set up your Business Inbox in Outlook" in assisted setup.
After this I created a web client for the test instance in IIS under "Microsoft Dynamics 365 Business Central Web Client" site. Then under "Bindings" use the self-signed cert for port 443. Was able to browse to the web client using https.
Under "Client Services" for the test instance I set the Web Client Base URL to https://<hostname>:443/<server instance>/WebClient
Under "SOAP Services" I checked the "Enable SSL" and for the SOAP Base URL I set it to https://<hostname>:11047/<server instance>/WS/
Under OData Services I set the OData Base URL to https://<hostname>:11048/<server instance>/ODataV4/
For the ports on this instance I'm using the following:
Management Services - 11045
Client Services - 11046
SOAP Services - 11047
OData Services - 11048
Development - 11049
I have made sure it wasn't a firewall issue as well.
In the Outlook client when I click on "Contact Insights" or "New" I'm getting the following error message:

The self-signed cert is valid and I have read the Microsoft documentation https://docs.microsoft.com/en-us/dynamics365/business-central/dev-itpro/deployment/configure-ssl-web-client-connection... Am I missing something hear?
Edit: Forgot to mention we are using Office 365 for our exchange server.