Translation:Take off your coat!
Ah, thank you for that clarification! The only implication I could think of, other than a sexual one, was some sort of medical examination - but even then, it would be a bit abrupt. At the doctor's, "Please undress" would be much more likely than: "Take off your clothes". In the UK, you might say to somebody coming in from bad weather: "Take off your (wet) things!", or just: "Let me take your coat", rather than: "Take off your clothes!". "The latter would sound as if you meant: "Get naked!", so you'd probably use the wonderfully vague and all-purpose: "things", which would be understood as outdoor things.
Раздевайтесь! means literally "Undress!" in the imperative tense. "Take off your clothes," is not wrong. It's correct as a translation for example when you're being examined by a doctor. But when you arrive at a Russian home or office, and the person greeting you says "Раздевайтесь!" he is telling you to take off your coat, jacket, scarf, earmuffs, gloves, hat, etc., essentially to "make yourself comfortable." He is not telling you to take off your clothes. That's the difference.
It should be OK, in my opinion. There is a bit of an old-fashioned "rule", in English, about not splitting the infinitive. Here, the infinitive is "to take off", not just "to take". So there is an argument that "take" and "off" should always stay together as if they were joined, not have intervening words. By the same principle, Star Trek's famous: "to boldly go" would be wrong! But the so-called "rule" is not rigorously observed these days, and, in some cases, will even make your English sound quite weird. So I think your translation is fine. If it wasn't accepted, submit an error report next time.
We do have a common phrase in English, "Take off your things," typically for removing your outdoor wear, and not so much implying becoming stark naked, but not specifically limited to coats, that seems more suitably ambiguous to capture the meaning of раздевайтесь. Not accepted 2/28/20, but shouldn't it be??