terminal not accepting password, doesn't say its incorrect, it just resets the prompt

I'm trying to do a DNS flush on my computer due to some internet connectivity issues. Every time I type in the command for this and it prompts me for my password, I type it in and press return. It doesn't say my password is incorrect or give me any error messages, it just restarts the prompt with my device name and username, then the blank box. I tried typing the password in incorrectly and it did pop up an error message saying "sorry, try again" so i typed in the correct password and it did the same thing. Clearly I'm getting the password correct it just keeps resetting. What is the issue here?