This may be due to the Timesheet Group authorities.
To check this, you can go to Timesheets > Timesheet Setup > then select Timesheet Groups.
From this screen, you can select a blue hyperlink in the ID column, which will display a pop-up showing all user authorities.
On this pop-up, you will be able to view the status of authorities in the "Timesheet Authority" column.
If this column is set to "None" for the respective Timesheet Group, the user will not have access.
You can adjust this column accordingly, with multiple entries possible for a single user.
Entries are added using the "New Lines" button.
Note: this page and pop-up are restricted to System Admin and Finance licenced users.
Refer to https://webwbdoc.atlassian.net/wiki/spaces/DOC/pages/705560923/Timesheet+Groups for more details.
