An unsecured or incorrectly secured fault was received from the other party. See the inner FaultException for the fault code and detail while trying to connect using XrmToolBox

While trying to create a new connection in XrmToolBox, we got the below error

We had used the Connection Wizard as the connection method

After failing a couple of more times, we realised the mistake.

For the user who is trying to log in, MFA is enabled.

So, instead we opted for the SDK Login control connection method.

Clicking Open Sdk Login Control button opens up the standard login control to connect to Dynamics 365.

Provide username, password, and click on login.

Enter the code (received on registered phone number).

Thus, using the SDK Login Control, we were able to connect successfully.

You can also connect by registering the Azure AD App

https://alphabold.com/connecting-to-mfa-enabled-microsoft-dynamics-365-using-xrmtoolbox/

Check the below article for further details and different ways to connect to Dynamics 365 using XrmToolBox

https://www.xrmtoolbox.com/documentation/for-users/connecting-to-an-organization/

Hope it helps..