Bom Dia Fabio,
Question for my understanding: When you say that "you edit", are you specifically referring to Web Editing a published workbook? That is, editing a published workbook view in the browser and not in Tableau Desktop?
If so, this could be a matter of conflicting permissions.
First, is the Project permissions allowed for both Web Edit, Save, and Save as? Are the project permissions set to "Managed by the Owner" or "Locked to Project"? If the Project is set for "Managed by the Owner" permissions, then the publisher of the workbook could have set content permissions to the individual workbook that supersede the project permissions. In other words, the user might have permission at the Project to save edited material, but not on that specific workbook.
Examine first the Project permissions (this example shows the Project permissions set at "Managed by the owner":
If "Managed by the owner" then, example and compare the individual workbooks permissions (example picture is the window the author will see at time of publishing). Make sure there are no conflicting permissions
Remember that Tableau evaluates permissions first at the User and then the group level. Explicitly denied permissions will over-ride explicit grants in many cases, so use implicit (unspecified) in most cases.
One of the best articles I've seen to help understand this, including a visual guide to how Tableau evaluates permissions in the proper order, can be found here: Understanding Tableau Permissions - The Information Lab
If this reponse helps you resolve the issue, please mark it as helpful and as having answered your question correctly.
Tableau Online Deployment Advisor