Editing challenge creates an error

[KarimChabrak]

I get following error when trying to edit following challenge

https://community.coinsence.org/space/beyond-borders/xcoin/challenge/overview?challengeId=29

{ "url": "/space/beyond-borders/xcoin/challenge/edit?id=29", "status": 500, "response": "

PHP Notice 'yii\base\ErrorException' with message 'Undefined offset: 0' \n\nin /var/www/coinsence/protected/modules/xcoin/views/challenge/edit.php:43\n\nStack trace:\n#0 /var/www/coinsence/protected/vendor/sentry/sentry/lib/Raven/Breadcrumbs/ErrorHandler.php(34): yii\base\ErrorHandler->handleError(8, 'Undefined offse...', '/var/www/coinse...', 43, Array)\n#1 /var/www/coinsence/protected/modules/xcoin/views/challenge/edit.php(43): Raven_Breadcrumbs_ErrorH...",
"textStatus": "error",
"xhr": {
"readyState": 4,
"responseText": "
PHP Notice 'yii\base\ErrorException' with message 'Undefined offset: 0' \n\nin /var/www/coinsence/protected/modules/xcoin/views/challenge/edit.php:43\n\nStack trace:\n#0 /var/www/coinsence/protected/vendor/sentry/sentry/lib/Raven/Breadcrumbs/ErrorHandler.php(34): yii\base\ErrorHandler->handleError(8, 'Undefined offse...', '/var/www/coinse...', 43, Array)\n#1 /var/www/coinsence/protected/modules/xcoin/views/challenge/edit.php(43): Raven_Breadcrumbs_ErrorHandler->handleError(8, 'Undefined offse...', '/var/www/coinse...', 43, Array)\n#2 /var/www/coinsence/protected/vendor/yiisoft/yii2/base/View.php(336): require('/var/www/coinse...')\n#3 /var/www/coinsence/protected/vendor/yiisoft/yii2/base/View.php(254): yii\base\View->renderPhpFile('/var/www/coinse...', Array)\n#4 /var/www/coinsence/protected/humhub/modules/ui/view/components/View.php(111): yii\base\View->renderFile('/var/www/coinse...', Array, Object(humhub\modules\xcoin\controllers\ChallengeController))\n#5 /var/www/coinsence/protected/vendor/yiisoft/yii2/web/Controller.php(49): humhub\modules\ui\view\components\View->renderAjax('edit', Array, Object(humhub\modules\xcoin\controllers\ChallengeController))\n#6 /var/www/coinsence/protected/modules/xcoin/controllers/ChallengeController.php(212): yii\web\Controller->renderAjax('edit', Array)\n#7 [internal function]: humhub\modules\xcoin\controllers\ChallengeController->actionEdit()\n#8 /var/www/coinsence/protected/vendor/yiisoft/yii2/base/InlineAction.php(57): call_user_func_array(Array, Array)\n#9 /var/www/coinsence/protected/vendor/yiisoft/yii2/base/Controller.php(157): yii\base\InlineAction->runWithParams(Array)\n#10 /var/www/coinsence/protected/vendor/yiisoft/yii2/base/Module.php(528): yii\base\Controller->runAction('edit', Array)\n#11 /var/www/coinsence/protected/vendor/yiisoft/yii2/web/Application.php(103): yii\base\Module->runAction('xcoin/challenge...', Array)\n#12 /var/www/coinsence/protected/vendor/yiisoft/yii2/base/Application.php(386): yii\web\Application->handleRequest(Object(humhub\components\Request))\n#13 /var/www/coinsence/index.php(31): yii\base\Application->run()\n#14 {main}
",
"status": 500,
"statusText": "Internal Server Error"
},
"dataType": "html",
"html": "
PHP Notice 'yii\base\ErrorException' with message 'Undefined offset: 0' \n\nin /var/www/coinsence/protected/modules/xcoin/views/challenge/edit.php:43\n\nStack trace:\n#0 /var/www/coinsence/protected/vendor/sentry/sentry/lib/Raven/Breadcrumbs/ErrorHandler.php(34): yii\base\ErrorHandler->handleError(8, 'Undefined offse...', '/var/www/coinse...', 43, Array)\n#1 /var/www/coinsence/protected/modules/xcoin/views/challenge/edit.php(43): Raven_Breadcrumbs_ErrorH...",
"error": {},
"errorThrown": "Internal Server Error",
"validationError": false
}