Hi @usahana,

According to the How do I use the Dashboard in the Canvas app guide, the lock symbol you're seeing (where the grade would usually be displayed) means that your teacher has hidden grade totals for the course.   The gray is just the randomly assigned default color for the course (you can change that if you'd like to using).  So overall I don't think there are any particular problems with the course, everything seems ot be functioning as designed.

I hope this info helps!

-Chris