LabWindows tcp client lost connection with a visual studio server when the window make other operations

I have an application LabWindows/cvi with a main window with menus and buttons.

This main window has a software module that is a client of a TCP/IP connection where the server is in another application created in Microsoft Visual Studio 2019. The name of the server is “SC”.

When I select a menu of the main LabWindows/cvi window and I left the menu open without selecting an item menu, the client TCP/IP stop receiving message from the server, while the server send correctly the messages.

I attach the software module that is a client of a TCP/IP connection writed in C in LabWindows/cvi

The LabWindows/cvi application with the main window and the server TCP/IP application are executed in the same PC.