Microsoft Dynamics 365 for Finance and Operations cannot connect to the specified Application Object Server (AOS) instance. ...

Microsoft Dynamics 365 for Finance and Operations cannot connect to the specified Application Object Server (AOS) instance. This error may be caused by one of the following conditions:
- The AOS instance may be too busy to accept additional connections.
- The AOS instance may still be initializing after Setup.
- The host name and port number in the configuration may be wrong.
If this problem persists, contact your system administrator.