It is working with my login, but yesterday one of our users was unable to access it.
It may be related to a corrupt user profile. A couple of weeks ago, the same user could not preview emails, but I could. Marketo tech support suggested deleting her user account and adding the account back after 5 minutes. I did this and she could preview the emails; unfortunately, the
smart lists she created no longer show her as the creator. They asked me to create an Idea to preserve this information - please vote for it.