Failure in big size file uploading via Web or windows client

I have modified the configuration, eg. php.ini, nginx.conf, config.php, as mentioned in user manual.

After that, the file uploading below 3GB is successfully but others fails.

The response in web browser is “locked” or “internal server error”. The response in client is “gateway timeout”.

Actually the max file size is set as 16GB.

Pls refer to the following server log file while uploading failure in web browser:

{“reqId”:“zo7c1LfJTakG8Dq1yyFz”,“level”:4,“time”:“2018-04-07T07:01:47+00:00”,“remoteAddr”:“192.168.0.20”,“user”:“tony”,“app”:“webdav”,“method”:“PUT”,“url”:"/remote.php/webdav/Share/Drivers/Desktop/MSI-880GM/MSI_880GM-E1.iso",“message”:“Exception: {“Exception”:“OCA\\DAV\\Connector\\Sabre\\Exception\\FileLocked”,“Message”:”\“Share\/Drivers\/Desktop\/MSI-880GM\/MSI_880GM-E1.iso\” is locked",“Code”:0,“Trace”:"#0 \/opt\/wwwroot\/Nextcloud\/apps\/dav\/lib\/Connector\/Sabre\/Directory.php(151): OCA\\DAV\\Connector\\Sabre\\File->put(Resource id #76)\n#1 \/opt\/wwwroot\/Nextcloud\/3rdparty\/sabre\/dav\/lib\/DAV\/Server.php(1096): OCA\\DAV\\Connector\\Sabre\\Directory->createFile(‘MSI_880GM-E1.is…’, Resource id #76)\n#2 \/opt\/wwwroot\/Nextcloud\/3rdparty\/sabre\/dav\/lib\/DAV\/CorePlugin.php(525): Sabre\\DAV\\Server->createFile(‘Share\/Drivers\/D…’, Resource id #76, NULL)\n#3 [internal function]: Sabre\\DAV\\CorePlugin->httpPut(Object(Sabre\\HTTP\\Request), Object(Sabre\\HTTP\\Response))\n#4 \/opt\/wwwroot\/Nextcloud\/3rdparty\/sabre\/event\/lib\/EventEmitterTrait.php(105): call_user_func_array(Array, Array)\n#5 \/opt\/wwwroot\/Nextcloud\/3rdparty\/sabre\/dav\/lib\/DAV\/Server.php(479): Sabre\\Event\\EventEmitter->emit(‘method:PUT’, Array)\n#6 \/opt\/wwwroot\/Nextcloud\/3rdparty\/sabre\/dav\/lib\/DAV\/Server.php(254): Sabre\\DAV\\Server->invokeMethod(Object(Sabre\\HTTP\\Request), Object(Sabre\\HTTP\\Response))\n#7 \/opt\/wwwroot\/Nextcloud\/apps\/dav\/appinfo\/v1\/webdav.php(76): Sabre\\DAV\\Server->exec()\n#8 \/opt\/wwwroot\/Nextcloud\/remote.php(162): require_once(’\/opt\/wwwroot\/Ne…’)\n#9 {main}",“File”:"\/opt\/wwwroot\/Nextcloud\/apps\/dav\/lib\/Connector\/Sabre\/File.php",“Line”:176}",“userAgent”:“Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/65.0.3325.181 Safari/537.36”,“version”:“12.0.3.3”}