diff --git a/app/Models/Foundation/Summit/CalendarSync/CalendarSyncInfoCalDav.php b/app/Models/Foundation/Summit/CalendarSync/CalendarSyncInfoCalDav.php
index 64dc0fb2..0619c8be 100644
--- a/app/Models/Foundation/Summit/CalendarSync/CalendarSyncInfoCalDav.php
+++ b/app/Models/Foundation/Summit/CalendarSync/CalendarSyncInfoCalDav.php
@@ -104,6 +104,13 @@ class CalendarSyncInfoCalDav extends CalendarSyncInfo
      */
     public function getServer(){
         $result = parse_url($this->user_principal_url);
+
+        if(!$result) throw new \InvalidArgumentException(sprintf("user_principal_url %s is invalid", $this->user_principal_url));
+        if(!isset($result['scheme']))
+            throw new \InvalidArgumentException(sprintf("user_principal_url %s is invalid", $this->user_principal_url));
+        if(!isset($result['host']))
+            throw new \InvalidArgumentException(sprintf("user_principal_url %s is invalid", $this->user_principal_url));
+
         return $result['scheme']."://".$result['host'];
     }
 
diff --git a/app/Services/Apis/CalendarSync/CalendarSyncRemoteFacadeFactory.php b/app/Services/Apis/CalendarSync/CalendarSyncRemoteFacadeFactory.php
index adcc21c3..4653ada4 100644
--- a/app/Services/Apis/CalendarSync/CalendarSyncRemoteFacadeFactory.php
+++ b/app/Services/Apis/CalendarSync/CalendarSyncRemoteFacadeFactory.php
@@ -13,6 +13,7 @@
  **/
 use App\Services\Apis\CalendarSync\ICalendarSyncRemoteFacadeFactory;
 use models\summit\CalendarSync\CalendarSyncInfo;
+use Illuminate\Support\Facades\Log;
 /**
  * Class CalendarSyncRemoteFacadeFactory
  * @package services\apis\CalendarSync
@@ -24,17 +25,23 @@ final class CalendarSyncRemoteFacadeFactory implements ICalendarSyncRemoteFacade
      * @return ICalendarSyncRemoteFacade|null
      */
     public function build(CalendarSyncInfo $sync_calendar_info){
-        switch($sync_calendar_info->getProvider()){
-            case CalendarSyncInfo::ProviderGoogle:
-                return new GoogleCalendarSyncRemoteFacade($sync_calendar_info);
-                break;
-            case CalendarSyncInfo::ProvideriCloud:
-                return new ICloudCalendarSyncRemoteFacade($sync_calendar_info);
-                break;
-            case CalendarSyncInfo::ProviderOutlook:
-                return new OutlookCalendarSyncRemoteFacade($sync_calendar_info);
-                break;
+        try {
+            switch ($sync_calendar_info->getProvider()) {
+                case CalendarSyncInfo::ProviderGoogle:
+                    return new GoogleCalendarSyncRemoteFacade($sync_calendar_info);
+                    break;
+                case CalendarSyncInfo::ProvideriCloud:
+                    return new ICloudCalendarSyncRemoteFacade($sync_calendar_info);
+                    break;
+                case CalendarSyncInfo::ProviderOutlook:
+                    return new OutlookCalendarSyncRemoteFacade($sync_calendar_info);
+                    break;
+            }
+            return null;
+        }
+        catch (\Exception $ex){
+            Log::warning($ex);
+            return null;
         }
-        return null;
     }
 }
\ No newline at end of file