I have noticed a few issues with the emailing system on the site. For example, I forgot my password and requested an email be sent to recover it and it never came (I ended up remembering what it was while I waited). I then wanted to test what would happen if I tried to create an account with the same email address I am using to really test this bug. The form submitted but I received no confirmation email to activate my account. Finally, I tried a few of the basic missions (level 4 and 5 in particular), that require an email be sent. After completing performing the correct steps for the mission, I never received the email.
If someone can confirm that there is an issue here, that would be great.
EDIT: It seems like this error only occurs when using a hotmail account. Have switched to my gmail account and it is all working now