If, when trying to log in, you receive the 'your email, FAN or password do not match' error then this means you've not entered your email or password correctly.
Double check you're entering your details and if they're still not allowing you in then try clicking on 'Forgotten Password?' as this may be the cause. You can also ask your club to check the email they have registered against your name and double check this against what you're typing in.
Your login details for Matchday are the same as those for myaccount.thefa.com.