diff --git a/source_modules/sdrpp_server_source/src/sdrpp_server_client.cpp b/source_modules/sdrpp_server_source/src/sdrpp_server_client.cpp
index 9b1e63d5..3480feab 100644
--- a/source_modules/sdrpp_server_source/src/sdrpp_server_client.cpp
+++ b/source_modules/sdrpp_server_source/src/sdrpp_server_client.cpp
@@ -42,8 +42,20 @@ namespace server {
 
         // Ask for a UI
         int res = getUI();
-        if (res == -1) { throw std::runtime_error("Timed out"); }
-        else if (res == -2) { throw std::runtime_error("Server busy"); }
+        if (res < 0) {
+            // Close client
+            close();
+
+            // Throw error
+            switch (res) {
+            case CONN_ERR_TIMEOUT:
+                throw std::runtime_error("Timed out");
+            case CONN_ERR_BUSY:
+                throw std::runtime_error("Server busy");
+            default:
+                throw std::runtime_error("Unknown error");
+            }
+        }
     }
 
     Client::~Client() {
@@ -234,7 +246,7 @@ namespace server {
         else {
             if (!serverBusy) { flog::error("Timeout out after asking for UI"); };
             waiter->handled();
-            return serverBusy ? -2 : -1;
+            return serverBusy ? CONN_ERR_BUSY : CONN_ERR_TIMEOUT;
         }
         waiter->handled();
         return 0;
diff --git a/source_modules/sdrpp_server_source/src/sdrpp_server_client.h b/source_modules/sdrpp_server_source/src/sdrpp_server_client.h
index d06c8499..e4f4b52f 100644
--- a/source_modules/sdrpp_server_source/src/sdrpp_server_client.h
+++ b/source_modules/sdrpp_server_source/src/sdrpp_server_client.h
@@ -71,6 +71,11 @@ namespace server {
         std::mutex handledMtx;
     };
 
+    enum ConnectionError {
+        CONN_ERR_TIMEOUT    = -1,
+        CONN_ERR_BUSY       = -2
+    };
+
     class Client {
     public:
         Client(std::shared_ptr<net::Socket> sock, dsp::stream<dsp::complex_t>* out);