nano /etc/systemd/system/MTProxy.service

[Unit]
Description=MTProxy
After=network.target

[Service]
Type=simple
WorkingDirectory=/opt/MTProxy/
ExecStart=/opt/MTProxy/objs/bin/mtproto-proxy -u nobody -p 8888 -H  443 -P a228$ -S a704c6af27e86da1eccf7e66c46c7324 -S cd305c6ce6d02ce57eee8fec3eab09b5 -S e0b157fdf6809e136dfef71bf5692d7f --aes-pwd proxy-secret  proxy-multi.conf -M 1
Restart=on-failure

[Install]
WantedBy=multi-user.target

-S <secret> -S <secret> -S <secret> -S <secret> -S <secret> -S <secret> -S <secret> -S <secret> -S <secret>

ExecStart=/opt/MTProxy/objs/bin/mtproto-proxy -u nobody -p 8888 -H  443 -P a228$ -S HEREEEEEEEEEEEEEE --aes-pwd proxy-secret  proxy-multi.conf -M 1
Restart=on-failure