Likely pulling it out to feed is stressful. I'd feed in the vivarium. They really don't appreciate being handled.
I'd let it settle in for a little while longer without pestering it. Also be sure the housing is up to snuff: lots of hides and leaves, nice and cool (below room temp is best) and moist.
Small worms (wild-caught, not purchased redworms) are usually taken easily, as well as mealworms, crickets, waxworms, small hornworms. Likely the issue is stress, though; once it gets comfortable enough to start feeding, it should eat almost anything (not likely centipedes or slugs, though). Checking to see what the previous owner was feeding it might be helpful as well.
There is a glut of crappy animal care articles on the web these days, so here is a decent one:
https://www.caudata.org/cc/species/A...A_opacum.shtml