Drupal cannot create sites/default/files even though permissions seemed to be set to standard I continue to get an error message regarding file permissions on a sandbox server running RHEL 7

$ drush wd-show
 ID   Date          Type      Severity  Message                                                                    
 398  15/Jun 20:15  file      error     The directory sites/default/files exists but is not writable and could not 
                    system              be made writable.                                                          
 397  15/Jun 20:15  file      error     The file permissions could not be set on sites/default/files.              
 396  15/Jun 20:14  file      error     The directory sites/default/files exists but is not writable and could not 
                    system              be made writable.                                                          
 395  15/Jun 20:14  file      error     The file permissions could not be set on sites/default/files.              
 394  15/Jun 20:12  file      error     The directory sites/default/files exists but is not writable and could not 
                    system              be made writable.                                                          
 393  15/Jun 20:12  file      error     The file permissions could not be set on sites/default/files.              
 392  15/Jun 20:12  file      error     The directory sites/default/files exists but is not writable and could not 
                    system              be made writable.                                                          
 391  15/Jun 20:12  file      error     The file permissions could not be set on sites/default/files.              
 390  15/Jun 20:11  file      error     The directory /var/www/drupal-private-file-system/tmp exists but is not    
                    system              writable and could not be made writable.                                   
 389  15/Jun 20:11  file      error     The file permissions could not be set on                                   
                                        /var/www/drupal-private-file-system/tmp.  


I have followed the model from Securing file permissions and ownership. Even though my file permissions are as such:

[dev@sandbox sites]$ ll
total 8
drwxr-x---. 6 dev apache   61 Jun  8 14:38 all
drwxr-x---. 4 dev apache   55 Jun 15 15:08 default
-rw-r-----. 1 dev apache 2365 May  6 23:13 example.sites.php
-rw-r-----. 1 dev apache  904 May  6 23:13 README.txt


and 

[dev@sandbox default]$ ll
total 24
drwxr-x---. 3 dev apache    37 Jun 10 13:35 behat-tests
drwxrwx---. 3 dev apache    35 Jun  5 15:21 files
-rw-r-----. 1 dev apache 24103 Jun  8 10:30 settings.php


The folder structure looks like the following...

[dev@sandbox sites]$ tree -d -L 2
.
├── all
│   ├── libraries
│   ├── modules
│   ├── tests
│   └── themes
└── default
    ├── behat-tests
    └── files


My question: Where did I go wrong? Is there something you see here that I don't?
I disabled SELINUX by changing to disabled.

$ cat /etc/sysconfig/selinux

# This file controls the state of SELinux on the system.
# SELINUX= can take one of these three values:
#     enforcing - SELinux security policy is enforced.
#     permissive - SELinux prints warnings instead of enforcing.
#     disabled - No SELinux policy is loaded.
SELINUX=disabled
# SELINUXTYPE= can take one of these two values:
#     targeted - Targeted processes are protected,
#     minimum - Modification of targeted policy. Only selected processes are protected. 
#     mls - Multi Level Security protection.
SELINUXTYPE=targeted 


I would love to understand SELinux better or how to tune it in regards to Drupal.