If you were sending e-mails, then it has nothing to do with Newgrounds, because you can't send e-mails from Newgrounds, so I assume you are using some mail website.
Back in the past I received notifications on my mailing service for my account being suspiciously active, but strangely that was not true and completely random, so you, like I did, should ignore that accidental accusation. It's done by machine. And since man made machines, machines are prone to errors. Just like humans....
VicariousE
Do you pay for this email account? Keep at them, call customer service, see if anyone else online has been blocked for the same reason... wish you luck.
Wow, I don't think I've ever seen a person with sooo many online accounts before!
Troisnyx
Given how everyone tends to be on many social networks these days, there's going to be a lot of accounts in a lot of places.
Thing is, no, I don't -- I've been using said e-mail address since 2008, but between last year and this year, this is the third time I have been blocked for the same reason.