Please check the password for the relevant data connections entered in AOI Administrator are the same as the ones used for logging in to the Dimensions databases, as follows:
Open AOI Administrator
Click Data Connections and select the applicable data connection
Re-enter the Password and click Update
Restart Excel and try to upload a journal again or retry using an existing template.
If this does not work for a journal template, then please try to re-create the journal and input the data manually.