RFC system error in system/destination &1

What causes this issue?

An error occurred during RFC communications.
Target system: <LS>&V2&</>
Function: <LS>&V3&</>
RFC message: <LS>&V4&</>

System Response

The function terminates.

How to fix this error?

Correct the error on the whole system and execute the command again.

Error message extract from SAP system. Copyright SAP SE.