You may have pending WordPress subscriptions already, in which case they won't let you sign up for new stuff until you confirm or delete the pending ones. How to do that?
1. Visit https://subscribe.wordpress.com/.
2. Enter your email address and click Request Details.
3. After requesting your details, you'll be sent an email with a link in it. WATCH FOR IT! By clicking the link, you'll be taken to a page where you can manage your subscriptions.
Check your email (look in the Spam folder, too), for something with a subject line like, "Activate your Email Subscription to: A More Positive Perspective". You may have missed a confirmation link. You may wonder, "WHY do I have to click so many @#$% links just to subscribe!?" It's to keep you safe from malicious people who would try to subscribe you to everything on the Internet and fill up your inbox! (In some places, this double opt-in check is required by law.)
To find out more, including how to control cookies, see here: