Make sure that your email address is spelt correctly (no spaces before or after the email address) and, that you've put in the correct password.
If you've forgotten your password, you can reset it here.
If “invalid email” still keeps on showing, you may not have an account with Marine Deals. This means that you need to create a new account.
Note that if you've placed an order online using the option to "Check out as Guest", then an account was not created and you will need to create an account.