There are two things that may cause this.
Go to User Menu (bottom left) > Settings > Term
1. If you are starting a new term, then click 'Create a New Term'.
2. If you are still within your current term, you will need to adjust your term dates to include the dates you can't see.
When you create a term you set the date when your term starts and ends, as well as the date when exams end. Once those dates are set, Shovel only shows dates within that range as active. Dates outside of that date range will be grayed out, the date picker will not show future dates, and Shovel will not allow information to be added to future dates beyond this range. Extend the date ranges accordingly.