Manager Steven Gerrard is concerned over Rangers' lack of bite after a goalless draw with FK Shkupi in Macedonia on Tuesday.
The Scottish Premier League side progressed to the Europa League second qualifying round 2-0 on aggregate.
But Gerrard told RangersTV: "There are things I'm pleased at, but I am concerned about the lack of quality in the final third."
Rangers will now face either Petrocub of Moldova or Croatian side Osijek.
Honved (HUN) 4 Rabotnicki (MKD) 0
Honved win 5-2 on aggregate
Shkupi (MKD) 0 Rangers (SCO) 0
Rangers win 2-0 on aggregate
Levski (BUL) 3 Vaduz (LIE) 2
Aggregate 3-3. Vaduz win on away goals