Your fundraising participant is locked out of their account. They need to access the Participant Control Panel to update their page, send emails, etc. and cannot.
For security reasons, participants will be locked out of the Participant Control Panel after multiple unsuccessful log-in attempts. They will only be locked out for 15 minutes and can then try again. There is a Reset Password link that they should use to update their password before being locked out, available from the Participant Control Panel log-in.
If you wish to assist them, log into your admin area and go to People -> Participants. Click on the participant in question. If they are currently locked out, a message will appear at the top of their profile: 'This user account is currently locked. Click here to Unlock.' You can unlock them there and also change their password for them, from this screen.