Hi Sameer,
I faced the same problem with connecting plug registration tool.
I found another way to connect plugin registration tool.
Just fallow the below steps what I have done I hope it will help you:
Step 1 : Select Visual studio Solution where your code(Plugin) is written then
Step 2: right click on solution Select Manage NuGet Packages for Solution, then
Step 3 : go to browse Search for pluginregistrationtool.
Step 4: then select Microsoft.CrmSdk.XrmTooling.PluginRegistrationTool and install it.
Step 5 : After installation select visual Studio Solution right click chose Open folder in file explore;
Step 6: Select packages\Microsoft.CrmSdk.XrmTooling.PluginRegistrationTool.9.0.2.3\tools.
Step 7: then run PluginRegistration.exe
And continue.. :)