If you've forgotten the W2 Portal password there is a Forgotten your password link available from the Portal login page that will send you out a new reset password link.
The reset link works for 24h, so it's possible that the link has expired and need to be reset.
For the users who haven't yet been able to login, if they go to the portal homepage and use the "Forgotten your password" link, this should send them a new password reset link so they can use that new one instead.
The number of attempts for a password to be entered incorrectly is 5. After that, the account will be locked and you will have to raise a support ticket to ask the support team to unlock your account.
Please note that this email can sometimes be misidentified as Spam and may appear in your Junk folder. If you haven't received the reset email and it's not in your junk folder please raise a support ticket and one of the team can find an alternative way to send you the reset link.