Are you a new user activating your account for the first time, you must use the temporary password in the invitation e-mail to get started.
For activated users, you need to use the password you created during the activation process.
For users who are activated, there is a "Forgot password" option you can use, it is called "Glemt passord".
Enter the e-mail adress associated with the account (the same one you received the invitation e-mail to) and select "Send meg lenke for endring av passord".
You will then receive an e-mail containing a link to reset your password, "Endre passord".
I dont don't remember the password my forgot new change