Management Reporter - Login failed for user ''. Reason: An attempt to login using SQL authentication failed. Server is configured for Windows authentication only

So you are trying to install Management Reporter
You have installed the services
You are trying to deploy the data mart or the legacy and no matter how many times you put in the sa password you get the error above.

How to fix?
-Use a higher version of Management Reporter. The version you are using is possibly not compatible with your SQL version.