Drupal 8.x

I am new to Drupal 8 and am starting by building a sample site.  I have everything setup right, but I'm getting the PDO connection error below.  I'm pretty sure it has to do with hostname but I can't figure out what.

My settings.php looks like this:

I'm converting a D7 site to D8.

The current D7 site leverages url parameters to display content (via views/contextual filters) based on the parameters:

example.com/?store=locationA displays products for locationA

example.com/?store=locationB displays products for locationB (etc)

I have written a D8 module that applies the parameters to the URL when selecting a specific store:

example.com/jump/store/locationA = example.com/?store=locationA

I am new to Drupal 8 and am starting by building a sample site.  I have everything setup right, but I'm getting the PDO connection error below.  I'm pretty sure it has to do with hostname but I can't figure out what.

My settings.php looks like this:

My "Apply" button is very long, so I think if I make the corresponding field width larger, it will be reduced.  I don't know where to go to change this.

I'm trying to create an event feed in Drupal 8. I was able to generate the feed but it supplies too much information (author name, publish date, etc). I only need a few fields like event date and title. How can I filter out the extra tags in Drupal? The RSS widget that is reading the fields does not have that option and I didn't see it in Drupal.

When I try to migrate content while I have the domain access module, I get this error

InvalidArgumentException: Field field_domain_all_affiliates is unknown. in Drupal\Core\Entity\ContentEntityBase->getTranslatedField() (line 587 of /var/www/web/core/lib/Drupal/Core/Entity/ContentEntityBase.php).

This field is in my content type, and I have excluded this field from my migration script.