BAPI_USER_CHANGE returns "Internal error: FM ADDR_PERS_COMP_MAINTAIN_COMPL"

If, using BAPI_USER_CHANGE, I attempt to add a telephone number to a user, I receive the error message: "Internal error: FM ADDR_PERS_COMP_MAINTAIN_COMPL, exception: 6" with the error number: 026. What can I do?