Would someone please help me understand why my query is not being accepted by Access? I’m at my wit’s end.

SELECT
    NCR.Stage
    , AG.ID AS AgeGroup
    , Count(*) AS AgeGroupCount
FROM (
    qry1 AG
    LEFT JOIN qry1 AGi ON (
        AG.ID = AGi.ID + 1
    )
)
LEFT JOIN qry2 AS NCR ON (
    AG.AgeGroupLowerLimit <= NCR.Age
    AND (
        AGi.ID IS NULL
        OR AGi.AgeGroupLowerLimit > NCR.Age
    )
)
GROUP BY
    NCR.Stage
    , NCR.AgeGroup
;

The problem is related to the second left join, with qry2.
I’m posting here because I expect it’s going to be something extremely simple I just don’t know to look for, and of course Access itself is extremely unhelpful.
Thank you!