Valid DSN Error and connection/compatibility error due to ReportServer database when attempting in-place upgrade from sql Server 2014 to sql Server 2016

The following error details are in the upgrade log:

The report server database is not a supported compatibility level or a connection cannot be established. Use Reporting Services Configuration Manager to verify the report server configuration and SQL Server management tools to verify the compatibility level.

The report server configuration is not complete or is invalid. Use Reporting Services Configuration Manager to verify the report server configuration.

The report server has already been upgraded to 2016.  The report config app on the report server looks normal.  REPORTS in this database continue to WORK properly before and after the report server upgrade to 2016.

We've deleted the account on the database and report server and re-added it.  We've re-selected the "ReportServer" database from the report config app and ran "Test Connection" with success. We're using the same domain account that was in use for 2014.

The report server has 2 instances.  We've applied the above attempts to both.

The last step will be to take out the existing ReportServer database and use the report server config app to "Create New" ReportServer database.  However, we would like to avoid this as we would have to manually re-deploy hundreds of reports to the server. ( And it might not solve the problem. )

Any ideas would be appreciated. Thanks.