This is probably the best place to start reading:
http://codex.ww.wp.xz.cn/FAQ_Troubleshooting#E-mailed_passwords_are_not_being_received
In general, in my own experience, the first question to ask is whether ANY e-mail is getting “through” from your web site/web hosting. In other words, is this a web hosting problem or is it only your WordPress software that cannot e-mail?
Yes, email is coming through everywhere else.
Not to belabour the point, but I am not clear from your response, “Yes, email is coming through everywhere else”, as to whether you are getting e-mail from other software on your web site/web hosting where WordPress is installed.
In my experience, most supposedly WordPress e-mail problems turn out to be problems with the web host’s e-mail server.
Everything on my site is functioning perfectly, except for the blog subscriptions.
Again, you have not mentioned whether you are currently able to receive any e-mail from your web hosting account. That is the only way to know if this is a WordPress-related problem or a problem with your web hosting.
At this point, I would suggest you contact your web hosting company’s Support folks and get them to ensure/demonstrate that your web hosting account can indeed successfully send you an e-mail. And that you receive it.
99% of recent WordPress e-mail problems turn out to be web hosting issues, typically some sort of spam prevention.
