There could be several reasons why after a successful installation of term sync you encounter an error when clicking on "Manage Term Store Sync Points." The most common one is due to the settings you selected when configuring your metadata service.
In Central Administration navigate to Manage Service Applications, highlight your managed metadata service connection (the line below your managed metadata service) and select properties from the ribbon. Ensure that the second option " This service application is the default storage location for column specific term sets. " is selected. If you find that it is not selected this is likely your issue. Please select and try again.