diff --git a/src/main/java/eu/siacs/conversations/ui/EditAccountActivity.java b/src/main/java/eu/siacs/conversations/ui/EditAccountActivity.java
index d192fa0c6..92d6f2093 100644
--- a/src/main/java/eu/siacs/conversations/ui/EditAccountActivity.java
+++ b/src/main/java/eu/siacs/conversations/ui/EditAccountActivity.java
@@ -33,6 +33,8 @@ import android.widget.EditText;
 import android.widget.ImageView;
 import android.widget.Toast;
 
+import com.google.common.base.CharMatcher;
+
 import org.openintents.openpgp.util.OpenPgpUtils;
 
 import java.net.URL;
@@ -69,13 +71,13 @@ import eu.siacs.conversations.utils.TorServiceUtils;
 import eu.siacs.conversations.utils.UIHelper;
 import eu.siacs.conversations.utils.XmppUri;
 import eu.siacs.conversations.xml.Element;
+import eu.siacs.conversations.xmpp.Jid;
 import eu.siacs.conversations.xmpp.OnKeyStatusUpdated;
 import eu.siacs.conversations.xmpp.OnUpdateBlocklist;
 import eu.siacs.conversations.xmpp.XmppConnection;
 import eu.siacs.conversations.xmpp.XmppConnection.Features;
 import eu.siacs.conversations.xmpp.forms.Data;
 import eu.siacs.conversations.xmpp.pep.Avatar;
-import eu.siacs.conversations.xmpp.Jid;
 
 public class EditAccountActivity extends OmemoActivity implements OnAccountUpdate, OnUpdateBlocklist,
         OnKeyStatusUpdated, OnCaptchaRequested, KeyChainAliasCallback, XmppConnectionService.OnShowErrorToast, XmppConnectionService.OnMamPreferencesFetched {
@@ -215,12 +217,12 @@ public class EditAccountActivity extends OmemoActivity implements OnAccountUpdat
                 removeErrorsOnAllBut(binding.accountJidLayout);
                 return;
             }
-            String hostname = null;
+            final String hostname;
             int numericPort = 5222;
             if (mShowOptions) {
-                hostname = binding.hostname.getText().toString().replaceAll("\\s", "");
-                final String port = binding.port.getText().toString().replaceAll("\\s", "");
-                if (hostname.contains(" ")) {
+                hostname = CharMatcher.whitespace().removeFrom(binding.hostname.getText());
+                final String port = CharMatcher.whitespace().removeFrom(binding.port.getText());
+                if (Resolver.invalidHostname(hostname)) {
                     binding.hostnameLayout.setError(getString(R.string.not_valid_hostname));
                     binding.hostname.requestFocus();
                     removeErrorsOnAllBut(binding.hostnameLayout);
@@ -243,6 +245,8 @@ public class EditAccountActivity extends OmemoActivity implements OnAccountUpdat
                         return;
                     }
                 }
+            } else {
+                hostname = null;
             }
 
             if (jid.getLocal() == null) {
diff --git a/src/main/java/eu/siacs/conversations/utils/Resolver.java b/src/main/java/eu/siacs/conversations/utils/Resolver.java
index b7e866a80..2afec6225 100644
--- a/src/main/java/eu/siacs/conversations/utils/Resolver.java
+++ b/src/main/java/eu/siacs/conversations/utils/Resolver.java
@@ -74,8 +74,8 @@ public class Resolver {
         }
     }
 
-    public static List<Result> fromHardCoded(String hostname, int port) {
-        Result result = new Result();
+    public static List<Result> fromHardCoded(final String hostname, final int port) {
+        final Result result = new Result();
         result.hostname = DNSName.from(hostname);
         result.port = port;
         result.directTls = useDirectTls(port);
@@ -83,6 +83,15 @@ public class Resolver {
         return Collections.singletonList(result);
     }
 
+    public static boolean invalidHostname(final String hostname) {
+        try {
+            DNSName.from(hostname);
+            return false;
+        } catch (IllegalArgumentException e) {
+            return true;
+        }
+    }
+
 
     public static boolean useDirectTls(final int port) {
         return port == 443 || port == 5223;