How to fix the Employee/UID/Login already exists
While creating new employee records, you may encounter a notification indicating that the employee's UID, Username, or Login ID already exists. 
These notifications signify that an existing employee in the platform shares the same UID, Email, or Login ID.
UID / Login-ID / User Already Exists!
In the event that you receive a notification indicating that the UID already exists, the first step is to search for the UID among the Live Employees.
If the UID is not located among the Live Employees, the next step is to search within the Archived Employees tab. 
If you locate the UID in the Archived Employees tab, you will need to update it. Begin by accessing the employee's details by clicking on the eye icon. After that, select the blue "Make this Employee Live" button to proceed. 
Subsequently, locate the employee once more in the Live Employees list and access their detailed information.
Carefully delete the UID along with any other duplicate fields, such as Login-ID and Email. To confirm your changes, be sure to click the Save Updates button.
Once you have made the necessary updates, you can return the employee to the archived status by selecting the 'Archive Employee' button.
Once you have completed these steps, you may proceed to create the new employee record. 