You say the civilization 'evolved from' human society, is this on Earth?
Metal - poor world: If not, one possibility is a planet which is very poor in the elements needed for 'conventional' technology -- iron, aluminum, titanium etc. for structural uses and machines, copper/silver/gold for wiring, silicon/germanium for electronics, platinum group metals for a catalysts used for a wide variety of things, thorium/uranium for nuclear power, praseodymium/neodymium for strong magnets, etc. etc.
Of the above listed elements only iron, copper, and maybe silicon are biologically essential for humans, and only in very small quantities that wouldn't require the existence of practical ores of those metals on a planet.
No access to ores: Or those ores might exist, but not be accessible -- if a planet was, say, almost entirely covered by deep oceans with the only land being biologically deposited limestone islands, and all the useful ores are under five miles of ocean.
Or maybe the people even live on living, "floating islands" (island sized water lilies or something... a situation like this is found in Jack Vance's The Blue World). In that case the ocean could be something like 200 miles deep (a hypothetical ocean planet: https://en.wikipedia.org/wiki/Ocean_planet ).
Or the setting might be in an artificial environment - either a space habitat of some type (O'Neill colony, "Halo" type ring, Niven ring, Dyson sphere) or even a sealed 'arcology' type environment on Earth. Such a structure wouldn't allow access to ores, etc. unless that was intentionally incorporated in the design. (This problem is discussed in the original Ringworld by Larry Niven.)
Competition: Accessible ores exist, but if you make steel or aluminum structures or copper wiring, etc., they become extremely attractive food for some local pest. (The iron, copper, etc. in the human body isn't in metallic form but part of proteins, so wouldn't necessarily be a target just because the pure metal is.)