diff --git a/app/src/main/java/com/cappielloantonio/tempo/ui/dialog/ServerSignupDialog.java b/app/src/main/java/com/cappielloantonio/tempo/ui/dialog/ServerSignupDialog.java
index 03a9d37b..dc58c260 100644
--- a/app/src/main/java/com/cappielloantonio/tempo/ui/dialog/ServerSignupDialog.java
+++ b/app/src/main/java/com/cappielloantonio/tempo/ui/dialog/ServerSignupDialog.java
@@ -116,6 +116,11 @@ public class ServerSignupDialog extends DialogFragment {
             return false;
         }
 
+        if (!server.matches("^https?://(.*)")) {
+            bind.serverTextView.setError(getString(R.string.error_server_prefix));
+            return false;
+        }
+
         return true;
     }
 
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index 7dbf1e98..f6c8b185 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -52,6 +52,7 @@
     <string name="download_title_section">Downloads</string>
     <string name="empty_string" />
     <string name="error_required">Required</string>
+    <string name="error_server_prefix">http or https prefix required</string>
     <string name="exo_download_notification_channel_name">Downloads</string>
     <string name="filter_info_selection">Select two or more filters</string>
     <string name="filter_title">Filter</string>