We couldn't get to Office 365 email from your on-premises environment. TCP port 443 has to be open on your firewall to connect ...

We couldn't get to Office 365 email from your on-premises environment. TCP port 443 has to be open on your firewall to connect to Office 365 email.  Click on the link 'get help fixing this issue' in the actions pane located on the right side of the screen for assistance.