diff --git a/lib/delphi/src/Thrift.Server.pas b/lib/delphi/src/Thrift.Server.pas
index 6521444..13c5762 100644
--- a/lib/delphi/src/Thrift.Server.pas
+++ b/lib/delphi/src/Thrift.Server.pas
@@ -350,7 +350,7 @@
       if client = nil then begin
         if FStop
         then Abort  // silent exception
-        else raise TTransportException.Create( 'ServerTransport.Accept() may not return NULL' );
+        else raise TTransportExceptionUnknown.Create('ServerTransport.Accept() may not return NULL');
       end;
 
       FLogDelegate( 'Client Connected!');