Drupal 8.x

In D6 i installed simplenews and mime-mail and I could mail html mails.

Now i have to install the mail system, but I have troubles to see the html mail correct.
What did i do:

I am attempting to Install Drupal 8 on FreeBSD using Apache and Postgresql.

When running drupal/core/install.php Apache responds:

xxx.xxx.xxx.xxx is currently unable to handle this request.

500

httpd-error.log shows:

[:error] [pid xxxxxx] [client xxxxxxx] PHP fatal error: Call to undefined function Symfony//Component//Yaml//ctype_digit() in ****

/usr/local/www/apache24/data/drupal/vendor/symfony/yaml/Inline.php on line 504

that line contains:

case ctype_digit($scalar):

Can anyone tell me what I need to do at this point?

Hi everyone, this is my first post, so i want to say hi first.
Forgive me my English, i'm not native speaker.
Few weeks ago, i started using drupal, after using wordpress for some time,
In wordpress i have many useful functions in my functions.php that i miss
in drupal, but time has come, when people/friends/clients ask:
- Do you build websites based on drupal...?
Creating and editing php loops, its not problem for me,
but in drupal, what shame of me, i've got lost easly, so many things

I created a JavaScript file which allows a user to run a mortgage calculator. It works fine stand alone in Textastic. Following the Drupal 8 documentation:

1. Added it to my custom theme under the js folder.
2. Created a new library in the info file called calculator
3. Added the js file reference under the calculator library
4. Created a basic page called mortgage calculator
5. Added a custom template for the calculator
6. Attached the calculator library in the custom twig template

Here is my mytheme.info.yml

Hi,

There is clear documentation about how to authenticate using REST, however this seems to be only for the use case of client-side rendering and api request (like angular). I can't seem to figure out how to handle this when using node.js as a frontend, where node.js interacts with drupal (using a websocket). Should I use sessions to set drupal cookies per user?

Regards,
Tim

Hello
How to add this code:

in head section of bartik theme?
Thank you