If the user gets the error message "Special char. are Not Allowed in City Field, Please Enter Again" That means the Source: POS>TRANSACTIONS>CUSTOMER
Why: The user has enter in a special character in the city field and these special characters are not allowed Example. Example: !@#$%^&*()_+ cannot be used when entering in any information.
Correction: When typing in the city please do no use special characters in this field
Wiki Link: Customer Creation