It is clear the active-sync bits are missing;
...
< MS-ASProtocolCommands: Sync,SendMail,SmartForward,SmartReply,GetAttachment,GetHierarchy,CreateCollection,DeleteCollection,MoveCollection,FolderSync,FolderCreate,FolderDelete,FolderUpdate,MoveItems,GetItemEstimate,MeetingResponse,Search,Settings,Ping,ItemOperations,ResolveRecipients,ValidateCert
< Public: OPTIONS, POST
< MS-ASProtocolVersions: 2.5,12.0,12.1,14.0,14.1
< MS-Server-ActiveSync: 14.1
...
And that is the problem on your (test)setup 
I am out of ideas so give my setup in key words and some test you could do:
My test setup
Local AD account provider
Email
Sogo
(not relevant but to be accurate)
File server
FTP server
MariaDB
Roundcube web mail
Statistics
Web server
rpm -q nethserver-sogo
nethserver-sogo-1.7.5-1.ns7.noarch
# virtual host setup (just this nothing else!)
config setprop sogod VirtualHost sogo.mydomain.tld
signal-event nethserver-sogo-update
config show sogod
sogod=service
ActiveSync=enabled
AdminUsers=admin
BackupTime=30 0
Certificate=
CustomEmailField=userPrincipalName
Dav=enabled
DraftsFolder=Drafts
MailAuxiliaryUserAccountsEnabled=YES
Notifications=Appointment,EMail
SOGoInternalSyncInterval=30
SOGoMaximumPingInterval=3540
SOGoMaximumSyncInterval=3540
SOGoMaximumSyncResponseSize=2048
SOGoMaximumSyncWindowSize=100
SentFolder=Sent
SessionDuration=1440
SxVMemLimit=512
TrashFolder=Trash
VirtualHost=sogo.mydomain.tld
WOWatchDogRequestTimeout=60
WOWorkersCount=10
status=enabled
cat /etc/httpd/conf.d/zzz_SOGo.conf
# ================= DO NOT MODIFY THIS FILE =================
#
# Manual changes will be lost when this file is regenerated.
#
# Please read the developer's guide, which is available
# at NethServer official site: https://www.nethserver.org
#
#
<VirtualHost *:80>
ServerName sogo.mydomain.tld
RedirectMatch 301 ^(?!/.well-known/acme-challenge/).* https://sogo.mydomain.tld
RewriteEngine On
RewriteCond %{HTTPS} !=on
RewriteRule (.*) https://%{SERVER_NAME}$1 [R,L]
</VirtualHost>
<VirtualHost *:443>
ServerName sogo.mydomain.tld
RedirectMatch ^/$ /SOGo
SSLEngine on
SSLCertificateFile "/etc/pki/tls/certs/localhost.crt"
SSLCertificateKeyFile "/etc/pki/tls/private/localhost.key"
# SOGo dav auto-discovery support is enabled
RedirectMatch ^/(dav|cal|card)$ /SOGo/dav/
RedirectMatch ^/.well-known/(caldav|carddav)$ /SOGo/dav/
# Sogo ActiveSync is enabled
<Location /Microsoft-Server-ActiveSync>
ProxyPass http://127.0.0.1:20000/SOGo/Microsoft-Server-ActiveSync retry=60 connectiontimeout=5 timeout=3600
</Location>
<Location /SOGo>
ProxyPass http://127.0.0.1:20000/SOGo retry=0
ProxyPassReverse http://127.0.0.1:20000/SOGo
SetEnv proxy-nokeepalive 1
</Location>
ProxyRequests Off
ProxyPreserveHost On
SetEnvIf Host (.*) REQUEST_HOST=$1
<Proxy http://127.0.0.1:20000/SOGo>
RequestHeader set "x-webobjects-server-port" "443"
RequestHeader set "x-webobjects-server-name" "%{REQUEST_HOST}e"
RequestHeader set "x-webobjects-server-url" "https://%{REQUEST_HOST}e/SOGo"
RequestHeader set "x-webobjects-server-protocol" "HTTP/1.0"
RequestHeader set "x-webobjects-remote-host" %{REMOTE_HOST}e env=REMOTE_HOST
## When using proxy-side autentication, you need to uncomment and
## adjust the following line:
# RequestHeader set "x-webobjects-remote-user" "%{REMOTE_USER}e"
AddDefaultCharset UTF-8
Require all granted
</Proxy>
Alias /SOGo.woa/WebServerResources/ /usr/lib64/GNUstep/SOGo/WebServerResources/
Alias /SOGo/WebServerResources/ /usr/lib64/GNUstep/SOGo/WebServerResources/
<Directory /usr/lib64/GNUstep/SOGo/>
AllowOverride None
Require all granted
<IfModule expires_module>
ExpiresActive On
ExpiresDefault "access plus 1 year"
</IfModule>
</Directory>
</VirtualHost>
something notable in the sogod logs?
(Administration) Log viewer > /var/sogo/sogo.log
Temporarily enable EAS debug logging by editing/etc/sogo.conf
(at the end) uncomment SOGoEASDebugEnabled
/* 80 Debug */
//SOGoDebugRequests = YES;
//SoDebugBaseURL = YES;
//ImapDebugEnabled = YES;
//LDAPDebugEnabled = YES;
//PGDebugEnabled = YES;
//MySQL4DebugEnabled = YES;
//SOGoUIxDebugEnabled = YES;
//WODontZipResponse = YES;
SOGoEASDebugEnabled = YES;
//WOLogFile = "/var/log/sogo/sogo.log";
(note this will be overwritten at nethserver-sogo-update event)
systemctl restart sogod
check if sogod is running and lets restart it:
(in web-gui) (Status) Services>sogod Restart
command line:
systemctl status sogod
systemctl restart sogod && systemctl status sogod
Lets test if (apache) redirects are causing troubles:
are the activ-sync bits still missing if you “override” the redirect from /Microsoft-Server-ActiveSync to /SOGo/Microsoft-Server-ActiveSync by putting SOGo in the url?
curl -v -k --user <user>:'<pass>' -X OPTIONS https://<FQDN_myhostname>/SOGo/Microsoft-Server-ActiveSync
you misspelled enabled (ensabled)