I tried to register with a weak password (on purpose) to check security. It works; four tries and three different errors (capital letters required, special characters required, min length required). However, I feel like a user hitting this issue accidentally would've given up after the third try. Perhaps it could be worth to check for multiple errors at once, and output them all to the user; e.g. "The password must mix case, and contain special characters, and have a minimum length of 8". Just an idea/feedback, mind you.