There are multiple things that can be tried when a user is unable to log into the system. Check the following to see if the issue is resolved.

1. Make sure that the user has a username listed.
  1. Go to Core > Users/Access > Profile > Edit User Profile Data 
  2. Enter the name of the user
  3. Under Sign In Information make sure that a username is listed.
2. Reset the user's password
  1. Go to Core > Users/Access > Profile > Edit User Profile Data
  2. Enter the name of the User
  3. Under Sign In Information select Set Temp Password
  4. Enter a generic password that the user can use to log in. The user will be prompted to change their password.
3. Have the user request their username/password. 
  1. From the login page, have the user select Forgot Username/Password.
  2. Have the user enter their email address. (Make sure that it is the same address that is in the system)
  3. Tell the user to follow the link the update their password.
4. Check for Duplicate Users in the System
  1. Go to Core > Users/Access > Profile > Edit User Profile Data
  2. Filter on All Roles
  3. Type in the name of the user
  4. Check to see if there are duplicate users. If so, check the username for both accounts.
  5. If the users both have the same username, either remove the duplicate user or change the username on one account to something different.