diff --git a/src/qt/optionsdialog.cpp b/src/qt/optionsdialog.cpp
index dd654a7abe27c..6d0904adb8c19 100644
--- a/src/qt/optionsdialog.cpp
+++ b/src/qt/optionsdialog.cpp
@@ -20,6 +20,7 @@
 #include <node/chainstatemanager_args.h>
 #include <netbase.h>
 #include <txdb.h>
+#include <util/strencodings.h>
 
 #include <chrono>
 
@@ -482,7 +483,10 @@ QValidator(parent)
 QValidator::State ProxyAddressValidator::validate(QString &input, int &pos) const
 {
     Q_UNUSED(pos);
-    // Validate the proxy
+    uint16_t port{0};
+    std::string hostname;
+    if (!SplitHostPort(input.toStdString(), port, hostname) || port != 0) return QValidator::Invalid;
+
     CService serv(LookupNumeric(input.toStdString(), DEFAULT_GUI_PROXY_PORT));
     Proxy addrProxy = Proxy(serv, true);
     if (addrProxy.IsValid())