Hi Phiinx,
Welcome to Community! It's great to hear that you've chosen QuickBooks Online Payroll to pay your staff with confidence. It's important that your employee is able to access their account effortlessly. I'd be happy to provide more information so you can get back to what you love!
Based on the information you've provided, I suggest having a look at the email address associated with the employee and ensure it's not associated with any other QuickBooks account or Workforce login. It's best to register them with a new email address to eliminate this type of outcome when they try to login as a member of your staff.
If the issue persists, please have your employee contact Workforce support for additional assistance with logging into their account.
Please feel free to reach back out with other questions. We'd be glad to assist!