Where system updates produce a '403: Forbidden' error - for example, during an employee rehire - there are two common causes.
Multiple active sessions
403 forbidden errors often occur when more than one active session is open.
Ask the user to log out and log back in.
Ensure no multiple portal tabs are open.
ModSecurity checks
Some text input may trigger ModSecurity, the security layer that blocks suspicious HTTP traffic. During a rehire, this can be caused by the email address and/or home address of the employee. Override the error as follows.
Remove the email and/or home address, then continue with the process.
You can re-enter these details later without triggering the error.