Syncing android => Server: one file fails

Hello
I have a 150mb file, which doesn’t get synced from android to the server. The error message on the client is simply: “Unknown Error”.

On the server side i get this exception:

{
   "reqId":"JUZ2JtkqH1mDjsCOyIuP",
   "level":4,
   "time":"2020-04-13T07:13:29+00:00",
   "remoteAddr":"XXX.XXX.XXX.XXX",
   "user":"USERNAME",
   "app":"webdav",
   "method":"PROPFIND",
   "url":"/remote.php/dav/uploads/USERNAME/8c53b67e57a82935652310f6a22f8486",
   "message":{
      "Exception":"OCP\\Files\\NotFoundException",
      "Message":"/USERNAME/files/8c53b67e57a82935652310f6a22f8486/0000000000000000-0000000010239999",
      "Code":0,
      "Trace":[
         {
            "file":"/var/www/html/lib/private/Files/Node/Folder.php",
            "line":137,
            "function":"get",
            "class":"OC\\Files\\Node\\Root",
            "type":"->",
            "args":[
               "/USERNAME/files/8c53b67e57a82935652310f6a22f8486/0000000000000000-0000000010239999"
            ]
         },
         {
            "file":"/var/www/html/apps/dav/lib/Connector/Sabre/SharesPlugin.php",
            "line":157,
            "function":"get",
            "class":"OC\\Files\\Node\\Folder",
            "type":"->",
            "args":[
               "/8c53b67e57a82935652310f6a22f8486/0000000000000000-0000000010239999"
            ]
         },
         {
            "file":"/var/www/html/apps/dav/lib/Connector/Sabre/SharesPlugin.php",
            "line":210,
            "function":"getShares",
            "class":"OCA\\DAV\\Connector\\Sabre\\SharesPlugin",
            "type":"->",
            "args":[
               {
                  "__class__":"OCA\\DAV\\Connector\\Sabre\\File"
               }
            ]
         },
         {
            "file":"/var/www/html/3rdparty/sabre/dav/lib/DAV/PropFind.php",
            "line":98,
            "function":"OCA\\DAV\\Connector\\Sabre\\{closure}",
            "class":"OCA\\DAV\\Connector\\Sabre\\SharesPlugin",
            "type":"->",
            "args":[
               "*** sensitive parameters replaced ***"
            ]
         },
         {
            "file":"/var/www/html/apps/dav/lib/Connector/Sabre/SharesPlugin.php",
            "line":213,
            "function":"handle",
            "class":"Sabre\\DAV\\PropFind",
            "type":"->",
            "args":[
               "{http_protocol//nextcloud.org/ns}sharees",
               {
                  "__class__":"Closure"
               }
            ]
         },
         {
            "function":"handleGetProperties",
            "class":"OCA\\DAV\\Connector\\Sabre\\SharesPlugin",
            "type":"->",
            "args":[
               {
                  "__class__":"Sabre\\DAV\\PropFind"
               },
               {
                  "__class__":"OCA\\DAV\\Connector\\Sabre\\File"
               }
            ]
         },
         {
            "file":"/var/www/html/3rdparty/sabre/event/lib/EventEmitterTrait.php",
            "line":105,
            "function":"call_user_func_array",
            "args":[
               [
                  {
                     "__class__":"OCA\\DAV\\Connector\\Sabre\\SharesPlugin"
                  },
                  "handleGetProperties"
               ],
               [
                  {
                     "__class__":"Sabre\\DAV\\PropFind"
                  },
                  {
                     "__class__":"OCA\\DAV\\Connector\\Sabre\\File"
                  }
               ]
            ]
         },
         {
            "file":"/var/www/html/3rdparty/sabre/dav/lib/DAV/Server.php",
            "line":1059,
            "function":"emit",
            "class":"Sabre\\Event\\EventEmitter",
            "type":"->",
            "args":[
               "propFind",
               [
                  {
                     "__class__":"Sabre\\DAV\\PropFind"
                  },
                  {
                     "__class__":"OCA\\DAV\\Connector\\Sabre\\File"
                  }
               ]
            ]
         },
         {
            "file":"/var/www/html/3rdparty/sabre/dav/lib/DAV/Server.php",
            "line":981,
            "function":"getPropertiesByNode",
            "class":"Sabre\\DAV\\Server",
            "type":"->",
            "args":[
               {
                  "__class__":"Sabre\\DAV\\PropFind"
               },
               {
                  "__class__":"OCA\\DAV\\Connector\\Sabre\\File"
               }
            ]
         },
         {
            "file":"/var/www/html/3rdparty/sabre/dav/lib/DAV/Server.php",
            "line":1666,
            "function":"getPropertiesIteratorForPath",
            "class":"Sabre\\DAV\\Server",
            "type":"->",
            "args":[
               "uploads/USERNAME/8c53b67e57a82935652310f6a22f8486",
               [
                  "{DAV:}creationdate",
                  "{DAV:}getetag",
                  "{http_protocol//owncloud.org/ns}permissions",
                  "{DAV:}getlastmodified",
                  "{http_protocol//owncloud.org/ns}id",
                  "{DAV:}getcontentlength",
                  "{http_protocol//owncloud.org/ns}favorite",
                  "{DAV:}resourcetype",
                  "{http_protocol//nextcloud.org/ns}sharees",
                  "{DAV:}displayname",
                  "{DAV:}getcontenttype",
                  "{http_protocol//nextcloud.org/ns}has-preview",
                  "{http_protocol//owncloud.org/ns}size"
               ],
               1
            ]
         },
         {
            "file":"/var/www/html/3rdparty/sabre/dav/lib/DAV/CorePlugin.php",
            "line":355,
            "function":"generateMultiStatus",
            "class":"Sabre\\DAV\\Server",
            "type":"->",
            "args":[
               {
                  "__class__":"Generator"
               },
               false
            ]
         },
         {
            "function":"httpPropFind",
            "class":"Sabre\\DAV\\CorePlugin",
            "type":"->",
            "args":[
               {
                  "absoluteUrl":"http_protocol//my.domain.tld/remote.php/dav/uploads/USERNAME/8c53b67e57a82935652310f6a22f8486",
                  "__class__":"Sabre\\HTTP\\Request"
               },
               {
                  "__class__":"Sabre\\HTTP\\Response"
               }
            ]
         },
         {
            "file":"/var/www/html/3rdparty/sabre/event/lib/EventEmitterTrait.php",
            "line":105,
            "function":"call_user_func_array",
            "args":[
               [
                  {
                     "__class__":"Sabre\\DAV\\CorePlugin"
                  },
                  "httpPropFind"
               ],
               [
                  {
                     "absoluteUrl":"http_protocol//my.domain.tld/remote.php/dav/uploads/USERNAME/8c53b67e57a82935652310f6a22f8486",
                     "__class__":"Sabre\\HTTP\\Request"
                  },
                  {
                     "__class__":"Sabre\\HTTP\\Response"
                  }
               ]
            ]
         },
         {
            "file":"/var/www/html/3rdparty/sabre/dav/lib/DAV/Server.php",
            "line":479,
            "function":"emit",
            "class":"Sabre\\Event\\EventEmitter",
            "type":"->",
            "args":[
               "method:PROPFIND",
               [
                  {
                     "absoluteUrl":"http_protocol//my.domain.tld/remote.php/dav/uploads/USERNAME/8c53b67e57a82935652310f6a22f8486",
                     "__class__":"Sabre\\HTTP\\Request"
                  },
                  {
                     "__class__":"Sabre\\HTTP\\Response"
                  }
               ]
            ]
         },
         {
            "file":"/var/www/html/3rdparty/sabre/dav/lib/DAV/Server.php",
            "line":254,
            "function":"invokeMethod",
            "class":"Sabre\\DAV\\Server",
            "type":"->",
            "args":[
               {
                  "absoluteUrl":"http_protocol//my.domain.tld/remote.php/dav/uploads/USERNAME/8c53b67e57a82935652310f6a22f8486",
                  "__class__":"Sabre\\HTTP\\Request"
               },
               {
                  "__class__":"Sabre\\HTTP\\Response"
               }
            ]
         },
         {
            "file":"/var/www/html/apps/dav/lib/Server.php",
            "line":319,
            "function":"exec",
            "class":"Sabre\\DAV\\Server",
            "type":"->",
            "args":[

            ]
         },
         {
            "file":"/var/www/html/apps/dav/appinfo/v2/remote.php",
            "line":35,
            "function":"exec",
            "class":"OCA\\DAV\\Server",
            "type":"->",
            "args":[

            ]
         },
         {
            "file":"/var/www/html/remote.php",
            "line":165,
            "args":[
               "/var/www/html/apps/dav/appinfo/v2/remote.php"
            ],
            "function":"require_once"
         }
      ],
      "File":"/var/www/html/lib/private/Files/Node/Root.php",
      "Line":203,
      "CustomMessage":"--"
   },
   "userAgent":"Mozilla/5.0 (Android) Nextcloud-android/3.11.0",
   "version":"18.0.3.0"
}

Any idea whats wrong here?

my setup:
nextcloud 18.0.3.0 is running via docker behind a traefik edge router/ssl terminator.
The admin panel does not report any errors and scan.nextcloud reports A+.

I had to replace http: with http_protocol because a new user cant post links ;/