diff --git a/app/build.gradle b/app/build.gradle
index 939c6f0c..345123ca 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -18,7 +18,7 @@ android {
         targetSdkVersion 22
 
         versionCode 84
-        versionName "0.9.1"
+        versionName "0.9.1.1"
 
         buildConfigField "java.util.Date", "buildTime", "new java.util.Date()"
     }
diff --git a/app/src/main/java/at/bitfire/davdroid/resource/DavResourceFinder.java b/app/src/main/java/at/bitfire/davdroid/resource/DavResourceFinder.java
index dfe591c6..fa370150 100644
--- a/app/src/main/java/at/bitfire/davdroid/resource/DavResourceFinder.java
+++ b/app/src/main/java/at/bitfire/davdroid/resource/DavResourceFinder.java
@@ -35,6 +35,7 @@ import at.bitfire.dav4android.DavResource;
 import at.bitfire.dav4android.UrlUtils;
 import at.bitfire.dav4android.exception.DavException;
 import at.bitfire.dav4android.exception.HttpException;
+import at.bitfire.dav4android.exception.NotFoundException;
 import at.bitfire.dav4android.property.AddressbookDescription;
 import at.bitfire.dav4android.property.AddressbookHomeSet;
 import at.bitfire.dav4android.property.CalendarColor;
@@ -413,20 +414,23 @@ public class DavResourceFinder {
             paths.add("/");
         }
 
-        for (String path : paths) {
-            if (!TextUtils.isEmpty(scheme) && !TextUtils.isEmpty(fqdn) && port != null && paths != null) {
-                HttpUrl initialContextPath = new HttpUrl.Builder()
-                        .scheme(scheme)
-                        .host(fqdn).port(port)
-                        .encodedPath(path)
-                        .build();
+        for (String path : paths)
+            try {
+                if (!TextUtils.isEmpty(scheme) && !TextUtils.isEmpty(fqdn) && port != null && paths != null) {
+                    HttpUrl initialContextPath = new HttpUrl.Builder()
+                            .scheme(scheme)
+                            .host(fqdn).port(port)
+                            .encodedPath(path)
+                            .build();
 
-                log.info("Trying to determine principal from initial context path=" + initialContextPath);
-                HttpUrl principal = getCurrentUserPrincipal(initialContextPath);
-                if (principal != null)
-                    return principal;
+                    log.info("Trying to determine principal from initial context path=" + initialContextPath);
+                    HttpUrl principal = getCurrentUserPrincipal(initialContextPath);
+                    if (principal != null)
+                        return principal;
+                }
+            } catch(NotFoundException e) {
+                log.warn("No resource found", e);
             }
-        }
         return null;
     }
 
diff --git a/app/src/main/java/at/bitfire/davdroid/ui/setup/LoginURLFragment.java b/app/src/main/java/at/bitfire/davdroid/ui/setup/LoginURLFragment.java
index 29fa18af..348a4513 100644
--- a/app/src/main/java/at/bitfire/davdroid/ui/setup/LoginURLFragment.java
+++ b/app/src/main/java/at/bitfire/davdroid/ui/setup/LoginURLFragment.java
@@ -7,6 +7,7 @@
  */
 package at.bitfire.davdroid.ui.setup;
 
+import android.app.Activity;
 import android.app.DialogFragment;
 import android.app.Fragment;
 import android.content.Context;
@@ -156,7 +157,9 @@ public class LoginURLFragment extends Fragment implements TextWatcher {
 
     @Override
     public void onTextChanged(CharSequence s, int start, int before, int count) {
-        getActivity().invalidateOptionsMenu();
+        Activity activity = getActivity();
+        if (activity != null)
+            activity.invalidateOptionsMenu();
     }
 
     @Override
diff --git a/dav4android b/dav4android
index 6a83ed5a..b77404b8 160000
--- a/dav4android
+++ b/dav4android
@@ -1 +1 @@
-Subproject commit 6a83ed5a370f92fb8d8440a6e4a06d9e2fa3dfcd
+Subproject commit b77404b82c6bae193754344ecb00b7e4be88797f