"Hij vertelde me dat hij in het huis van zijn ouders was blijven wonen."
Translation:He told me that he had continued to live in his parents' house.
It is accepted (now - I don't know if it was a week ago) but frustratingly marks the possessive apostrophe as a typo. There is no direct way of reporting this, except to file an independent bug report, since "my answer should be accepted" is not an option, where your answer was accepted, but wrongly said to contain a typo. :(
It's a bug. Take a screenshot and file a report here: https://support.duolingo.com/hc/en-us/requests/new