Hi @PedroAbrunhosa,
In OJS 3.0 the Administrator’s permissions are more limited. This is going to be improved in 3.1 and until then there is a workaround of making the Admin user the Journal Manager or logging in as a Journal Manager (see After upgrading to OJS3 Administrator has few rights - #4 by asmecher).
Regarding your second problem, can the user who has the role of Section Editor, Reviewer, and Reader see the submission page but can’t open the file(s) or can they not see the submission at all? And what stage of the workflow is the submission at when the user is not able to access it?
Thanks,
Amanda Stevens
Public Knowledge Project Team