Drupal 8.x

I am actually doing tutorials for iPHONE and ANDROID development. Perhaps some golang.
I wanted to create a paid service to do articles and tutorials... I thought I would put out some requests for comments to see what the state of the art in this field would be... what DRUPAL would offer.

Ideally, a student would pay $x for 3 months.. with a recurring payment option.
What are my options?

I would also do this in Drupal 8 if this is an option. not proud.

Just installed latest Drupal 8 (for testing purposes and learning twig). After database update site remained in maintenance mode:

Notice: Undefined offset: 0 in contact_menu_local_tasks_alter() (line 96 of core/modules/contact/contact.module).
Warning: Invalid argument supplied for foreach() in contact_menu_local_tasks_alter() (line 96 of core/modules/contact/contact.module).

Hi
Installed Drupal 8 (6) to my hosting provider and its not looking too good...
Sent in a ticket to provider for help and got this response? Not too helpful for my skill level and hope someone might know how to fix?

site is
www.signee.com.au

There was a screenshot of a css page which had hundreds of ? in little diamonds.
zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz

Reply from ticket

There are two possible causes for this issue...

Hi all,

I am new to the Drupal Community. I want to show 5 recent article link (the most recent articles) on the left sidebar, but this ain't working.

What have I done already? I made 10 articles..
I went to the block area and customized the recent content block, did not restrict it to any page or admin or whatsoever. Just stated that I want to show articles, saved and voila...

The problem: it does not show on the sidebar, even when I dragged it to the first sidebar area...

What am I doing wrong?

PS: working on localhost

Hey all, I'm looking into using Drupal to build a stock art website, similar to https://shiftworship.com

Mostly what I'm looking to be able to do is allow everyone to view the images, but only allow paying members to download the full size images. Anyone got any suggestions for modules that would help with this?

(I had a friend helping me on the website but he's had to back out due to his own time constraints. Sadly my scripting skills are pretty limited.)

Hello.
Basically the subject is my question, why aren't the RSS feed implemented as a module and why are they enabled by default. For some people it may be an unnecessary feature.
Thank you.