Could you please let me know what type of content you would like to edit? Do you have any custom template assigned to the page you are trying to edit? And do you experience the same issue when editing content on the other pages?
I can also suggest that you open a ticket and provide us with backend credentials or send us an archived copy of your project and the backup of your database in order to research the issue in more depth.
Do you want to have your say in the Sitefinity development roadmap? Do you want to know when a feature you requested is added or when a bug fixed? Explore the Telerik Public Issue Tracking
system and vote to affect the priority of the items