You will need to enter the email or domain into your "Blocked Senders" list manually.
Click on the "More" button in the menu bar at the top of the email list. Scroll down the drop down box and click on "View Source". This should open a page that show you all the information about the email.
Look through that information and you should fined numerous references to the email address that sent you the email.
Once you have that information you need then click on your username at the top right hand side then select "Settings" then click on "Mail" in the left hand column and select "Blocked Senders". The Blocked Senders list will open.
In the email box click "Add" and enter the email address or the domain that you found when you searched through the source.
Once you have done that you will find that you have just wasted about ten minutes of your life because Spammers are constantly changing their sending email address and domain and as a result it really is pointless trying to block them.
The "Block Senders" list is only of use to block genuine email addresses that you no longer wish to receive emails from.
When spam emails arrive in your email account you are best just to delete it. Do not open it because all you are doing is alerting the spammer that they have found an active email account and more spam is bound to follow..
