Please check the following:
1. If you have any Email Sender or SMTP plugin, please deactivate those during the test.
2. You’ll not get email, if the receiver is the same sender. Make sure the “From Email” (Forums > Settings > Email) is not the same subscriber email.
2. If the “From Email” domain doesn’t have website domain name (e.g.: [email protected], but website is example.com) it may tracked as spam, you should check in spam box.
3. Some hosting services, or some Antispam plugins try to cache emails and those are not being sent immediately. You should wait 1-30 min (e.g.: on some GoDaddy hosting plans you receive emails in 45 min).
4. If you’re using GMail Fetch services, go to Gmail Settings > Accounts and Import and click on “Check mail now” link to load all new comments from website email server.
5. First email is the Subscription Confirmation Email, you should click on confirmation link and confirm your subscription to certain forum/topic. If you don’t get Subscription confirmation email and don’t confirm it you’ll not get future comments. Sometimes the confirmation email go to spam-box and user don’t check it. You should check in spam-box as well.
6. Test it as real as possible. You should use new IP, new emails and new accounts. The best way to ask your friend to post a reply with Subscription and Subscription Confirmation. Then reply him.
7. Make sure you don’t reply to your topic or post. It doesn’t send email notification if you reply to your topic.