Why does email get blocked?

Related questions

1. Is a plus sign valid in an email address?
2. Will an email send if one address is wrong?
3. What happens if I open a spam email?
4. Can you find someone's email address?
5. How can I find out if someone has an email address?
6. How do I know if my email has been received?
7. How can I check if an email address exists?
8. How can I confirm an email was delivered?
9. What happens if email address is wrong?
10. Can I get hacked by opening an email?

Tags

1. #blacklisted
2. #message
3. #email
4. #spammers
5. #emails
6. #reached
7. #block
8. #passed
9. #content
10. #domain
11. #blocked
12. #recipients
13. #filters
14. #through
15. #because