MS Exchange 2016 - Basicconfig Fragen

server {
    listen 80;
    server_name webmail.domain.de autodiscover.domain.de;
    return 301 https://$host$request_uri;
}

server {
    tcp_nodelay on;
    listen 443;
    
    ssl on;
    ssl_certificate /etc/letsencrypt/live/domain.de/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/domain.de/privkey.pem;
    ssl_session_timeout 5m;
    ssl_protocols TLSv1;
    ssl_ciphers ALL:!ADH:!EXPORT56:RC4+RSA:+HIGH:+MEDIUM:+LOW:+SSLv3:+EXP;
    ssl_prefer_server_ciphers on;

    server_name webmail.domain.de autodiscover.domain.de;

    location / {
           return 301 https://webmail.domain.de/owa;
    }

    proxy_http_version      1.1;
    proxy_read_timeout      360;
    proxy_pass_header       Date;
    proxy_pass_header       Server;
    proxy_pass_header      Authorization;
    proxy_set_header        Host $host;
    proxy_set_header        X-Real-IP $remote_addr;
    proxy_set_header        X-Forwarded-For  $proxy_add_x_forwarded_for;
    proxy_pass_request_headers on;
    more_set_input_headers 'Authorization: $http_authorization';  
    proxy_set_header Accept-Encoding "";  
    more_set_headers -s 401 'WWW-Authenticate: Basic realm="ex001"';  
    proxy_buffering off;
    proxy_set_header Connection "Keep-Alive";  

    location ~* ^/owa { proxy_pass https://ex001; }
    location ~* ^/Microsoft-Server-ActiveSync { proxy_pass https://ex001; }
    location ~* ^/ecp { proxy_pass https://ex001; }
    location ~* ^/rpc { proxy_pass https://ex001; }
    location ~* ^/autodiscover { proxy_pass https://ex001; }
}

proxy_pass https://ex001

server {
        listen       80;
        server_name webmail.domain.de autodiscover.domain.de;
 
        # Redirect any HTTP request to HTTPS
        return 301 https://$server_name$request_uri;
 
        error_log  /var/log/nginx/exchange-error.log;
        access_log /var/log/nginx/exchange-access.log;
}

server {
        listen       443;
        server_name webmail.domain.de autodiscover.domain.de;
 
        # Enable SSL
        ssl                     on;
        ssl_certificate         /etc/letsencrypt/live/domain.de/fullchain.pem;
        ssl_certificate_key     /etc/letsencrypt/live/domain.de/privkey.pem;
        ssl_session_timeout     5m;
 
        # Set global proxy settings
        proxy_read_timeout      360;
 
        proxy_http_version 1.1;
        proxy_pass_request_headers on;
 
        proxy_pass_header       Date;
        proxy_pass_header       Server;
 
        proxy_set_header        Host $host;
        proxy_set_header        X-Real-IP $remote_addr;
        proxy_set_header        X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header        Accept-Encoding "";  
 
        more_set_input_headers 'Authorization: $http_authorization';  
        proxy_set_header Accept-Encoding "";  
        more_set_headers -s 401 'WWW-Authenticate: Basic realm="ex001"';  
 
        location /owa           { proxy_pass https://ex001/owa; }
        location /OWA           { proxy_pass https://ex001/OWA; }        
        location /EWS          { proxy_pass https://ex001/EWS; }
        location /ews          { proxy_pass https://ex001/ews; }        
        location /Microsoft-Server-ActiveSync { proxy_pass https://ex001/Microsoft-Server-ActiveSync; }
        location /mapi           { proxy_pass https://ex001/mapi; }
        location /MAPI          { proxy_pass https://ex001/MAPI; }        
        location /rpc           { proxy_pass https://ex001/rpc; }
        location /RPC           { proxy_pass https://ex001/RPC; }
        location /ecp           { proxy_pass https://ex001/ecp; }
        location /ECP           { proxy_pass https://ex001/ECP; }
        location /oab            { proxy_pass https://ex001/oab; }
        location /OAB            { proxy_pass https://ex001/OAB; }        
        location /autodiscover           { proxy_pass https://ex001/autodiscover; }
        location /Autodiscover           { proxy_pass https://ex001/Autodiscover; }
 
        error_log /var/log/nginx/exchange-ssl-error.log;
        access_log /var/log/nginx/exchange-ssl-access.log;
}

	Testing HTTP Authentication Methods for URL https://webmail.domain.de/rpc/rpcproxy.dll?06507b04-6a1e-42d8-b77c-3fc87cd6c3d5@domain.de:6002.
 	The HTTP authentication test failed.
 	 Tell me more about this issue and how to resolve it
 	
	Additional Details
 	
Not all the required authentication methods were found.
Methods Found: Basic
Methods Required: NTLM
HTTP Response Headers:
Connection: keep-alive
request-id: 9f6bf746-2a5e-4219-992b-3f47779ed6f5
Content-Length: 0
Date: Tue, 21 Feb 2017 20:35:00 GMT
Server: Microsoft-IIS/8.5
WWW-Authenticate: Basic realm="ex001"  
Elapsed Time: 328 ms.