My Gantt chart has all the correct information in it but the bars are stuck at the first date. I have a Mac and think it may be a setting on my computer. I attached the information I am working with. Any help would be appreciated.

Task Start Date Days to Complete Task 1 22-May 13 Gantt Chart Task 2 31-May 9 Task 3 5-Jun 9 22-May 1-Jun 11-Jun 21-Jun 1-Jul 11-Jul 21-Jul 31-Jul Task 4 15-Jun 14 Task 1 Task 5 21-Jun 9 Task 6 1-Jul 5 Task 2 Task 7 8-Jul 7 Task 3 Task 8 15-Jul 12 Task 4 Task 5 Task 6 Task 7 Task 8 Task 8 Task 7 Task 6 Task 5 Task 4 Task 3 Task 2 Task 1 Start Date 15-Jul 8-Jul 1-Jul 21-Jun 15-Jun 5-Jun 31-May 22-May Days to Complete 12 7 5 9 14 9 9 13