AVETMISS error codes/4755
AVS error 4755
ErrorNAT00120Subject identifier
What it means
Overlapping activity dates for the same subject and Client identifier (nationally recognised).
How to fix it
Remove or correct the overlapping unit enrolment.
Does RTObase catch this automatically?
Yes, RTObase validates this against your own data before you lodge and takes you straight to the field to fix it, so this error usually never reaches AVS.
Got a whole report of errors? Explain them all at once.
Error explainer →Guidance only, not a substitute for lodgement. Meaning current as of July 2026; AVS rules and error/warning status can change between collection periods. Always re-validate in NCVER AVS before you submit.
Never see this error again
RTObase validates your AVETMISS data as you go and deep-links you straight to the field to fix, so most AVS errors never happen. Start free.