RE: Unable to login plugin registration tool
There are two easy ways to login Plugin Registration Tools:
1- Use XRM Tool Box
Click on the Plugin Registration Tools you will get the following popup :




sign your Dynamics 365/CRM account:

Second way:
If you work with Visual Studio go to your Plugin Properties and select References and go to Tools bar and select

Then search Microsoft.crmsdk..

Add in Plugin and when you build your Plugin go to folder where you builded and select packages. Inside of Packages folder select
Microsoft.CrmSdk.XrmTooling.PluginRegistrationTool.9.1.0.20
then select the tools folder inside this folder click on the Plugin Registration.exe

and follow to create a new connection wizard.
You must sign in without issue.