Could not pack parameter &1

What causes this issue?

An error occurred in the TMS communication layer.
Command: <LS>&V2&</>
System: <LS>&V3&</>
Function: <LS>TMS_CI_ENCODE_PARAMETER</>
Error: <LS>&V4&</>
Parameter: <LS>&V1&</>

System Response

The function terminates.

How to fix this error?

The specified parameter could not be coded for transfer. Correct the
error and execute the command again.

Error message extract from SAP system. Copyright SAP SE.