How To Fix TD223 - Forms beginning with 'Y' or 'Z' are reserved for customers

SAP Error Message - Details

• Message type: E = Error

• Message class: TD - SAPscript: Text editor, composer, forms, styles and fonts

• Message number: 223

• Message text: Forms beginning with 'Y' or 'Z' are reserved for customers

What causes this issue?

As a customer, you have tried to create a style whose name does not
begin with 'Y' or 'Z'.
As an SAP employee, you have tried to create a style whose name begins
with 'Y' or 'Z'.

System Response

The initial letters 'Y' and 'Z' are reserved for customers, all others
for SAP.

How to fix this error?

Select a name with a valid initial letter.

Error message extract from SAP system. Copyright SAP SE.