by Julian Corrêa.
Bill,inmy databaseusernamefield is populatedonlywith numbersbecause it comes fromanother system.
The fact that thedatain the fieldisnumericUSERNAMEhas nothing todo withthe error that I reported.
Found it isa permission problem.TheuserWebServicehas to bethe site administrator.
See https://tracker.moodle.org/browse/MDL-42639.
Tks