diff --git a/twidere/src/main/java/org/mariotaku/twidere/activity/support/APIEditorActivity.java b/twidere/src/main/java/org/mariotaku/twidere/activity/support/APIEditorActivity.java
index ed58cbc3f..4a01d25dd 100644
--- a/twidere/src/main/java/org/mariotaku/twidere/activity/support/APIEditorActivity.java
+++ b/twidere/src/main/java/org/mariotaku/twidere/activity/support/APIEditorActivity.java
@@ -37,6 +37,7 @@ import android.widget.Toast;
 import org.mariotaku.twidere.R;
 import org.mariotaku.twidere.model.ParcelableCredentials;
 import org.mariotaku.twidere.provider.TwidereDataStore.Accounts;
+import org.mariotaku.twidere.util.TwitterAPIFactory;
 
 import static org.mariotaku.twidere.util.ParseUtils.parseString;
 import static org.mariotaku.twidere.util.Utils.getNonEmptyString;
@@ -75,7 +76,11 @@ public class APIEditorActivity extends BaseSupportDialogActivity implements OnCh
     public void onClick(final View v) {
         switch (v.getId()) {
             case R.id.save: {
-                saveAndFinish();
+                if (checkApiUrl()) {
+                    saveAndFinish();
+                } else {
+                    mEditAPIUrlFormat.setError(getString(R.string.wrong_url_format));
+                }
                 break;
             }
             case R.id.api_url_format_help: {
@@ -85,6 +90,10 @@ public class APIEditorActivity extends BaseSupportDialogActivity implements OnCh
         }
     }
 
+    private boolean checkApiUrl() {
+        return TwitterAPIFactory.verifyApiFormat(String.valueOf(mEditAPIUrlFormat.getText()));
+    }
+
     @Override
     public void onContentChanged() {
         super.onContentChanged();
diff --git a/twidere/src/main/java/org/mariotaku/twidere/provider/TwidereDataProvider.java b/twidere/src/main/java/org/mariotaku/twidere/provider/TwidereDataProvider.java
index e3087d662..a054adf22 100644
--- a/twidere/src/main/java/org/mariotaku/twidere/provider/TwidereDataProvider.java
+++ b/twidere/src/main/java/org/mariotaku/twidere/provider/TwidereDataProvider.java
@@ -943,8 +943,12 @@ public final class TwidereDataProvider extends ContentProvider implements Consta
             builder.setNumber(statusesCount);
             builder.setColor(pref.getNotificationLightColor());
             setNotificationPreferences(builder, pref, pref.getHomeTimelineNotificationType());
-            nm.notify("home_" + accountId, NOTIFICATION_ID_HOME_TIMELINE, builder.build());
-            Utils.sendPebbleNotification(context, notificationContent);
+            try {
+                nm.notify("home_" + accountId, NOTIFICATION_ID_HOME_TIMELINE, builder.build());
+                Utils.sendPebbleNotification(context, notificationContent);
+            } catch (SecurityException e) {
+                // Silently ignore
+            }
         } finally {
             statusCursor.close();
             userCursor.close();
@@ -1043,9 +1047,13 @@ public final class TwidereDataProvider extends ContentProvider implements Consta
             builder.setStyle(style);
             builder.setColor(pref.getNotificationLightColor());
             setNotificationPreferences(builder, pref, pref.getMentionsNotificationType());
-            nm.notify("mentions_" + accountId, NOTIFICATION_ID_MENTIONS_TIMELINE,
-                    builder.build());
-            Utils.sendPebbleNotification(context, notificationContent);
+            try {
+                nm.notify("mentions_" + accountId, NOTIFICATION_ID_MENTIONS_TIMELINE,
+                        builder.build());
+                Utils.sendPebbleNotification(context, notificationContent);
+            } catch (SecurityException e) {
+                // Silently ignore
+            }
         } finally {
             statusCursor.close();
             userCursor.close();
@@ -1238,8 +1246,12 @@ public final class TwidereDataProvider extends ContentProvider implements Consta
             builder.setStyle(style);
             builder.setColor(pref.getNotificationLightColor());
             setNotificationPreferences(builder, pref, pref.getDirectMessagesNotificationType());
-            nm.notify("messages_" + accountId, NOTIFICATION_ID_DIRECT_MESSAGES, builder.build());
-            Utils.sendPebbleNotification(context, notificationContent);
+            try {
+                nm.notify("messages_" + accountId, NOTIFICATION_ID_DIRECT_MESSAGES, builder.build());
+                Utils.sendPebbleNotification(context, notificationContent);
+            } catch (SecurityException e) {
+                // Silently ignore
+            }
         } finally {
             messageCursor.close();
             userCursor.close();
diff --git a/twidere/src/main/java/org/mariotaku/twidere/util/TwitterAPIFactory.java b/twidere/src/main/java/org/mariotaku/twidere/util/TwitterAPIFactory.java
index 1cda87f38..a83820ee5 100644
--- a/twidere/src/main/java/org/mariotaku/twidere/util/TwitterAPIFactory.java
+++ b/twidere/src/main/java/org/mariotaku/twidere/util/TwitterAPIFactory.java
@@ -9,7 +9,9 @@ import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
 import android.text.TextUtils;
 import android.util.Pair;
+import android.webkit.URLUtil;
 
+import com.squareup.okhttp.HttpUrl;
 import com.squareup.okhttp.OkHttpClient;
 import com.squareup.okhttp.internal.Internal;
 
@@ -59,7 +61,6 @@ import java.util.concurrent.TimeUnit;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
-import javax.net.ssl.SSLContext;
 import javax.net.ssl.SSLSocketFactory;
 
 import static android.text.TextUtils.isEmpty;
@@ -175,7 +176,7 @@ public class TwitterAPIFactory implements TwidereConstants {
         return TwitterAPIFactory.getInstance(context, getEndpoint(credentials, cls), credentials, cls);
     }
 
-    public static Endpoint getEndpoint(ParcelableCredentials credentials, Class<?> cls) {
+    public static Endpoint getEndpoint(ParcelableCredentials credentials, Class<?> cls) throws APIFormatException {
         final String apiUrlFormat;
         final boolean sameOAuthSigningUrl = credentials.same_oauth_signing_url;
         final boolean noVersionSuffix = credentials.no_version_suffix;
@@ -202,6 +203,8 @@ public class TwitterAPIFactory implements TwidereConstants {
         }
         final String endpointUrl;
         endpointUrl = getApiUrl(apiUrlFormat, domain, versionSuffix);
+        if (endpointUrl == null || HttpUrl.parse(endpointUrl) == null)
+            throw new APIFormatException(apiUrlFormat);
         if (credentials.auth_type == ParcelableCredentials.AUTH_TYPE_XAUTH || credentials.auth_type == ParcelableCredentials.AUTH_TYPE_OAUTH) {
             final String signEndpointUrl;
             if (!sameOAuthSigningUrl) {
@@ -209,6 +212,8 @@ public class TwitterAPIFactory implements TwidereConstants {
             } else {
                 signEndpointUrl = endpointUrl;
             }
+            if (signEndpointUrl == null || HttpUrl.parse(signEndpointUrl) == null)
+                throw new APIFormatException(apiUrlFormat);
             return new OAuthEndpoint(endpointUrl, signEndpointUrl);
         }
         return new Endpoint(endpointUrl);
@@ -246,9 +251,13 @@ public class TwitterAPIFactory implements TwidereConstants {
         params.add(Pair.create(name, typedData));
     }
 
+    public static boolean verifyApiFormat(String format) {
+        return URLUtil.isValidUrl(getApiBaseUrl(format, "test"));
+    }
+
     public static String getApiBaseUrl(String format, final String domain) {
         if (format == null) return null;
-        final Matcher matcher = Pattern.compile("\\[(\\.?)DOMAIN(\\.?)\\]").matcher(format);
+        final Matcher matcher = Pattern.compile("\\[(\\.?)DOMAIN(\\.?)\\]", Pattern.CASE_INSENSITIVE).matcher(format);
         if (!matcher.find()) {
             // For backward compatibility
             format = substituteLegacyApiBaseUrl(format, domain);
@@ -398,4 +407,10 @@ public class TwitterAPIFactory implements TwidereConstants {
             return te;
         }
     }
+
+    public static class APIFormatException extends RuntimeException {
+        public APIFormatException(String format) {
+            super("Wrong api format " + format);
+        }
+    }
 }
diff --git a/twidere/src/main/java/org/mariotaku/twidere/util/net/NetworkUsageUtils.java b/twidere/src/main/java/org/mariotaku/twidere/util/net/NetworkUsageUtils.java
index 3b37334e0..6a959fa32 100644
--- a/twidere/src/main/java/org/mariotaku/twidere/util/net/NetworkUsageUtils.java
+++ b/twidere/src/main/java/org/mariotaku/twidere/util/net/NetworkUsageUtils.java
@@ -22,6 +22,7 @@ package org.mariotaku.twidere.util.net;
 import android.content.ContentResolver;
 import android.content.ContentValues;
 import android.content.Context;
+import android.util.Log;
 
 import com.squareup.okhttp.Interceptor;
 import com.squareup.okhttp.OkHttpClient;
@@ -30,6 +31,7 @@ import com.squareup.okhttp.RequestBody;
 import com.squareup.okhttp.Response;
 import com.squareup.okhttp.ResponseBody;
 
+import org.mariotaku.twidere.Constants;
 import org.mariotaku.twidere.model.RequestType;
 import org.mariotaku.twidere.provider.TwidereDataStore.NetworkUsages;
 import org.mariotaku.twidere.util.Utils;
@@ -39,7 +41,7 @@ import java.io.IOException;
 /**
  * Created by mariotaku on 15/6/24.
  */
-public class NetworkUsageUtils {
+public class NetworkUsageUtils implements Constants {
     public static void initForHttpClient(Context context, OkHttpClient client) {
         client.networkInterceptors().add(new NetworkUsageInterceptor(context));
     }
@@ -71,7 +73,11 @@ public class NetworkUsageUtils {
             final Response response = chain.proceed(request);
             values.put(NetworkUsages.KILOBYTES_RECEIVED, getBodyLength(response.body()) / 1024.0);
             final ContentResolver cr = context.getContentResolver();
-            cr.insert(NetworkUsages.CONTENT_URI, values);
+            try {
+                cr.insert(NetworkUsages.CONTENT_URI, values);
+            } catch (IllegalStateException e) {
+                Log.e(LOGTAG, "Unable to log network usage", e);
+            }
             return response;
         }
 
diff --git a/twidere/src/main/java/org/mariotaku/twidere/util/net/OkHttpRestClient.java b/twidere/src/main/java/org/mariotaku/twidere/util/net/OkHttpRestClient.java
index 4678b4271..6f13c0ca8 100644
--- a/twidere/src/main/java/org/mariotaku/twidere/util/net/OkHttpRestClient.java
+++ b/twidere/src/main/java/org/mariotaku/twidere/util/net/OkHttpRestClient.java
@@ -264,4 +264,5 @@ public class OkHttpRestClient implements RestHttpClient {
             }
         }
     }
+
 }