Здравствуйте,

Опубликовал exchange 16 через Nginx, все работает корректно за исключением ActiveSync и iPhone клиентов.
Проблема заключается в том, что не отправляются любые вложение размер которых больше 1 килобайта.
При отправке почтовый клиент сообщает "Сбой отправки сообщения" "Это сообщение было отклонено сервером"


ОС Ubuntu 16.04, nginx/1.13.5

Exchange.conf

server {

listen 443 ssl http2;
server_name mail.exchange.com autodiscover.exchange.com;

ssl_certificate /etc/letsencrypt/live/mail.exchange.com/fullchain.pem;
ssl_certificate_key /etc/letsencrypt/live/mail.exchange.com/privkey.pem;
ssl_trusted_certificate /etc/letsencrypt/live/mail.exchange.com/fullchain.pem;

# add_header Strict-Transport-Security "max-age=15768000; includeSubDomains; preload" always;
# add_header X-Content-Type-Options nosniff always;

include exchange_proxy.conf;

proxy_ssl_verify off;

location / {
return 301 https://mail.exchange.com/owa;
}

location = /favicon.ico {
empty_gif;
access_log off;
}

location ~* ^/owa {
proxy_pass https://exchange;
proxy_http_version 1.1;
proxy_set_header Connection "";
}

location ~* ^/Microsoft-Server-ActiveSync {
proxy_pass https://exchange;
proxy_http_version 1.1;
proxy_set_header Connection "";
}

location ~* ^/autodiscover {
proxy_pass https://exchange;
proxy_http_version 1.1;
proxy_set_header Connection "";
}

#########################################

exchange_proxy.conf

client_max_body_size 0;
client_body_buffer_size 128k;

proxy_read_timeout 3h;
proxy_send_timeout 3h;
proxy_connect_timeout 3h;
keepalive_timeout 3h;

proxy_buffers 16 32k;
proxy_buffer_size 64k;
proxy_busy_buffers_size 64k;
proxy_temp_file_write_size 64k;

proxy_pass_header Date;
proxy_pass_header Server;
proxy_pass_header Authorization;

proxy_pass_request_headers on;

large_client_header_buffers 8 32k;


# more_set_input_headers 'Authorization: $http_authorization';

proxy_http_version 1.1;
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 "";
proxy_set_header Connection "Keep-Alive";

# more_set_headers -s 401 'WWW-Authenticate: Basic realm="10.11.11.11"';

proxy_buffering off;
proxy_request_buffering off;

#########################################

ssl.conf

ssl_dhparam /etc/ssl/certs/dhparam.pem;
ssl_session_timeout 1d;
ssl_session_cache shared:SSL:50m;
ssl_session_tickets off;
ssl_protocols TLSv1.2;
ssl_ciphers 'ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA256';
ssl_prefer_server_ciphers on;
# ssl_ecdh_curve secp384r1;
ssl_stapling on;
ssl_stapling_verify on;

#########################################

upstream.conf

upstream exchange {
server 10.11.11.11:443;
}



В логах при отправке:

IP - user@exchange.com [09/Sep/2017:13:38:23 +0300] "POST /Microsoft-Server-ActiveSync?User=user@exchange.com&DeviceId=FDBV17HMPH1VDDJDFRGIS0K8ES&DeviceType=iPhone&Cmd=SendMail HTTP/2.0" 400 166 "-" "Apple-iPhone8C2/1501.537200001" "-"