Please direct your technical question to the MuleSoft forum. This forum is closely monitored by the Training team as well as the developer and instructor communities so you'll get your questions answered quickly.
A critical element of a large scale, self-study program is peer to peer support - which means that the more questions and solutions we can find on the forum, the better we can make the experience for everyone, including you.
Also, don't worry! You can take the assessment quiz multiple times. It has no tie to your certification, and is only used to help you prepare.