Unable to modify the SQL Server Maintenance Plan

I am using Microsoft SQL Server 2014 (SP2) (KB3171021) Standard Edition (64-bit) and I have created one Database Maintenance Plan on this server. I am able to modify all of the properties of the plan, however when I try to select the databases it gives me the following Error:

This task requires the connection to be initialized.

And when I click on "ok" I can see the following window but unable to see any database in it:

Can anyone explain this or give me any solution on this?

In order to access the "Local Server Connection" (creds you connected with in SSMS) to view databases instead of a specifically named saved connection, you have to launch SSMS as an administrator.

By default with UAC enabled, it won't ask when you open it, so you have to right-click and select "Run As Administrator" -- or you can save a shortcut that's set to always Run As Administrator.