My Google Classroom student is seeing a message indicating they're not in my class.

If you’re using Google Classroom connected classes and a student sees an error message indicating that they are not in your class or that they need to be added to your class when trying to access an assignment, there are a few things that could be happening:

Your student didn't log into Edpuzzle with their Google Classroom email.
To fix this, have the student log out of their current account and then log in again from by selecting the "Log In" button at the top of the page, then “I’m a Student,” and finally the “Sign In with Google” option. Make sure they select the email address associated with their Google Classroom account in the Google Sign-In pop-up. 

Your student created a new Edpuzzle account by accident and used an email address different from their Google Classroom email.
Similar to the above solution, tell the student to log into Edpuzzle using Google Sign-In and selecting the email address associated with their Google Classroom account. There's no need to delete the new account they created, as it will automatically be deactivated if not used. 

The student wasn't on your Google Classroom roster when the class was imported to Edpuzzle.
To update your class list to reflect your current Google Classroom enrollment, select the class from your My Classes list. Go to the "Class members" tab. On the right, click the "Import students" button. Once updated, the student should be able to access their assignments by signing into Edpuzzle with the same email they use for Google Classroom.

The student is trying to access the wrong assignment or an assignment from another class.
On Edpuzzle, assignments have a different link for each class. Even if the assignment is the same, each class will have a different link for the version of the assignment created for that class. Make sure that you’ve shared the specific assignment link for that student’s class with them.
To help prevent errors like this, always use the “Post on Google Classroom” option when creating the assignment. With this function, our system will automatically share the correct assignment links across your classes.