Allow anonymous users to subscribe to newsletter/mailing list My aim: 
Client side: Have a block in the front page to allow any user (including anonymous users) to input their names and email addresses to subscribe the newsletter. Administration Side: being able to see the mailing list and send out newsletter to these emails. 

What I have got:
I downloaded and enabled the follow modules: Mail System, Mime Mail, Mime Mail Action, Mime Mail CSS Compressor, Simplenews, SMTP Authentication. 

I am using Drupal 7 with Bootstrap theme.

What I have done:
I have added a new simplenews block in the front page only, styled a little bit. In permission section, I ticked both ANONYMOUS USER and AUTHENTICATED USER for 'Subscribe to newsletters' option.

Problems: 
I input my email and clicked the subscribe button in the block as a anonymous users, there is an error:


  Unable to send e-mail. Contact the site administrator if the problem persists.


Followed by a notice:


  You will receive a confirmation e-mail shortly containing further instructions on how to complete your subscription.


The SMTP Authentication module doesn't work for my account because it said my php doesn't have ssl enabled, which I don't know how to do? I have enabled ssl module in my apache, but what shall I do next? 

Also I then see no subscribers added when I log on as an administrator later. 

Question:
How can get let anonymous subscribe to mailing list and how can I create newsletter? Any instructions on how to achieve this? Am I using the wrong modules?
Sounds like your site can not send e-mails for whatever reason.

The default newsletter settings require to confirm a subscription, you can disable that in the newsletter settings, optionally also only for testing until you've figured the e-mail problem out.

Unconfirmed subscriptions aren't displayed in the UI, that's why you can't see anything.

Instructions on how to use and configure Simplenews can be found in the README.txt and the online documentation.

Note: You're asking a lot of different questions, and your actual problem (sending e-mails being broken) has nothing to do with initial question (you might not have known that, so that's ok). Remember that you're supposed to accept a (single) answer as the correct one, how can you do that if you ask multiple, different questions?