There are two secuirty matrix options you will need to check for FieldBook to work.
System administrators will need to access the security matrix from: Organisation -> Settings -> Organisation -> Security Matrix.
- 'Submit timesheet for others' allows any user access level ticked, to submit a timesheet for anyone in their organisation.
- 'Assign tasks to FieldBook' will keep any task in the users task list, if the user finds it in FieldBook. This is also user access level specific.