Every time I try to enter code in my courses, the session expires. Clicking on the "Restart Session" icon does not resolve the problem.
If you start another DataCamp session in a new tab, with the same account, it will automatically stop the original one. This could manifest itself as a "Your session expired" message.
It can also manifest itself as an "Oops, something went wrong" error message in Projects.
As a first step, make sure you close out additional tabs and windows with a DataCamp session. Once that is done, you should click on the "Restart Session" icon. If the problem persists, please reach out to the DataCamp Support team.