Logging into new forum - "Authentication failed"

Good evening,
I have just popped in to ask a question and realised the forum is different.
I have logged in on my tablet as it automatically filled in the username and password. However, I tried to log in on my laptop, but it says “Authentication failed”, so I assume the password is incorrect. There is not ‘forgotten password’ button.
How do I find out what my password is or how do I reset it.
Thank you.

Go to the self service page and reset your password:

Thank you, I think that will work. Unfortunately, I can’t use it as I have a fresh install and can’t access my email at the moment. I will come back if I am still having problems.