Logfile (errors), what to do?

Hey guys,

i’m using ownCloud for a couple of month now and i’m pretty happy. Everything works fine and as expected, only the Logfile shows a lot of errors (though everything works perfectly fine, as i said).

So here’s the error message that repeats every couple seconds:

Debug carddav

Exception: {"Message":"HTTP\/1.1 401 No basic authentication headers were found","Exception":"Sabre\DAV\Exception\NotAuthenticated","Code":0,"Trace":"#0 \/www\/htdocs\/[my-hosting-username]\/cloud\/lib\/private\/connector\/sabre\/auth.php(157): Sabre\DAV\Auth\Backend\AbstractBasic->authenticate(Object(Sabre\DAV\Server), 'ownCloud')\n#1 \/www\/htdocs\/[my-hosting-username]\/cloud\/lib\/private\/connector\/sabre\/auth.php(127): OC\Connector\Sabre\Auth->auth(Object(Sabre\DAV\Server), 'ownCloud')\n#2 \/www\/htdocs\/[my-hosting-username]\/cloud\/3rdparty\/sabre\/dav\/lib\/DAV\/Auth\/Plugin.php(118): OC\Connector\Sabre\Auth->authenticate(Object(Sabre\DAV\Server), 'ownCloud')\n#3 [internal function]: Sabre\DAV\Auth\Plugin->beforeMethod(Object(Sabre\HTTP\Request), Object(Sabre\HTTP\Response))\n#4 \/www\/htdocs\/[my-hosting-username]\/cloud\/3rdparty\/sabre\/event\/lib\/EventEmitterTrait.php(105): call_user_func_array(Array, Array)\n#5 \/www\/htdocs\/[my-hosting-username]\/cloud\/3rdparty\/sabre\/dav\/lib\/DAV\/Server.php(456): Sabre\Event\EventEmitter->emit('beforeMethod', Array)\n#6 \/www\/htdocs\/[my-hosting-username]\/cloud\/3rdparty\/sabre\/dav\/lib\/DAV\/Server.php(254): Sabre\DAV\Server->invokeMethod(Object(Sabre\HTTP\Request), Object(Sabre\HTTP\Response))\n#7 \/www\/htdocs\/[my-hosting-username]\/cloud\/apps\/contacts\/appinfo\/remote.php(84): Sabre\DAV\Server->exec()\n#8 \/www\/htdocs\/[my-hosting-username]\/cloud\/remote.php(137): require_once('\/www\/htdocs\/w00...')\n#9 {main}","File":"\/www\/htdocs\/[my-hosting-username]\/cloud\/3rdparty\/sabre\/dav\/lib\/DAV\/Auth\/Backend\/AbstractBasic.php","Line":70}

This is a problem since the log file gets very big …

Server configuration
Operating system:
Web server:
Database: mysql 5.6.30
PHP version: 5.6.23
ownCloud version (see ownCloud admin page): 8.2.7

Please see this FAQ providing all known info about this log entry: