FPX1003E Invalid suffix on `function_code` call to FPXGXDR (SUFFIX = `suffix`).

Explanation
 The user-written program passed a function code
with an invalid suffix to the exit. The invalid suffix is specified
in the message.

System action
 Processing ends with an abend code of 3599.

User response
 Make sure that a valid suffix is appended to
the function code. Valid suffixes are '1' through '9'.