Resetting credentials for MPI project

Hello,

I am trying to run my first MPI project and have a problem with credentials. Long story short, I have entered credentials and then realised I didn`t actually registered. Now, every time I`m starting the project prompt says: Credentials for <username> rejected connecting to <PCname>.

I wonder, how do I change the credentials I`ve entered and should have I registered with some specific name and password depending on PC name, windows username, etc. ?

Thank you.