RFC communications error with system/destination &1

What causes this issue?

An RFC error occurred in the TMS communications layer.
Target system: <LS>&V2&</>
Function: <LS>&V3&</>
RFC message: <LS>&V4&</>

System Response

The function terminates.

How to fix this error?

Correct the error and execute the command again.

Error message extract from SAP system. Copyright SAP SE.