You mentioned that you have installed a PI AF server. The tool that is captured in the screenshot is PI SDK Utility which can be used to test connection to PI Server (the data archive for time-series data) instead of PI AF Server. I guess either you haven't installed the data archive component after installing the PI AF Server or it wasn't started up after installation, hence it is unreachable.
If you want to test a connection to PI AF Server instead, you can try to use PI System Explorer (the management tools for PI AF) instead.
Thank you very much for your advice , this problem has been solved. Thanks!