Check the date range of the Time Reporting Period for these Timesheets. The application has the capability to restrict posting to only time periods where the last day of the period is before the current date. If the end of the Time Reporting Period is today or in the future, these are considered 'Future' Timesheets. To allow future Timesheets to post turn on the option in the Administration, Project Management, Timesheet Options: Check the box to 'Allow posting of future Timesheets'. In general, only "Save" button is needed. "Apply to all resources" are more for the default Time entry options and New UX options.