The syntax is wrong. You need to remove the square brackets and change to upper case:
LOAD USERID, GROUPID ;
SQL SELECT "User_ID" as USERID, "GroupID" as GROUPID
Further, you need to have a reducing field also - a field that links the table(s) in Section Access to the real data. Is this the GROUPID, or?
See A Primer on Section Access. This post is about QlikView and not Qlik Sense, but most things are the same. The only difference is really that NTNAME is replaced by USERID and GROUP.