C5W4 Exercise 4 - EncoderLayer

I have passed all of the exercises bar one (EncoderLayer). I have been trying for about 10 hours to work out why my code is not working. I have searched throughout the discussion forum, online, and github, but to no avail. I’ve given up and tried to submit so i can just get it over with and get my certificate but when i do I am given a 0/100. My subscription finishes soon and i do not want to have to pay for another month… Please can an admin look over my code and identify where my issue is. It is beyond stressing me out.

{edited to cleanliness}

@Edward - in the future, please start your own thread for your questions.