The sentence you entered was "He doesn't like to working in groups.", which is ungrammatical in English. "Don't" is among the automatically accepted contractions on Duolingo, so it should work for any instance of "do not".
Please don't use the sentence discussions for reports, as that only clutters them up. We do get the ones you submit through the report function, and they're easier to verify and work with, so it saves us time as well. Thank you! :)
Hei, Tusen tak! I was actually attempting to get back to the same question again to comment that I was sorry - I had actually made a typo. I assure you I definitely do not make a habit of cluttering up the discussion boards - I've hardly used them at all since I started using DuoLingo 14 months ago. Sorry to have done so on this occasion. I know, I really should be sending this entire message in Norwegian by now after so many lessons
Bare hyggelig, Rose!
No worries, and apologies if you felt singled out. I didn't mean to imply that you make a habit of it; my second paragraph was intended more as a general reminder, as you're definitely not alone in doing it from time to time.