If you are unable to save your schedule - It may be corrupted.  to fix this you will need to create the schedule again from scratch. 
To do this on the web portal:

• Go to the thermostat you are having trouble with
• Click the schedule tab
• Select "Repeat Schedule Setup"
• Follow the on screen instructions
• When finished setting up schedule click complete

You schedule should now be working.
To verify it is working - make an edit to your schedule and try to save it.  If you can save it you're good.