You'll want to verify the following for your classes/groups:
  1. Core > School > Departments & Courses - are your courses set to "Record Attendance: Yes"?
  2. onCampus > Procedure > Academics (or other group types using Attendance) > Set Section Information - are these tied to a Block?
  3. onRecord > Settings > Scheduling Setup > Schedule Sets - is that block tied to a meeting time on your schedule set?
You'll also want to check access dates:
  1. onCampus > Settings > Group Page Access to make sure teachers have access as of the correct date. 
  2. onRecord > Settings > Scheduling Setup > Schedule Sets - make sure teachers have access as of the correct date. 
  3. onRecord > Settings > Scheduling Setup > Schedule Sets - verify the Start Date of the Schedule Set is to the correct date.