program file to configure flex smarts do and flex radios

There are many YouTube instruction videos available on configuring third party programs. Fldigi is a case in point that explained the need to add a slice configuration file in order to interface with the Flex. It's not easy and takes work but it's worth the effort.

I think you are going to find out that every station is unique and much like a thumb print.  HRD (free or paid version) does work fine depending on what you are doing with it (Radio Control, Logbook, etc).  If you are mostly using DM780, then I would recommend using Minideluxe as your interface to DM780 and not use their radio control.  
If it 'stops working' then it must have been working, so that means you do have it correctly configured initially.    I would recommend you start with Minideluxe first:  https://github.com/krisp/MiniDeluxe/wiki
de va3mw

Not to argue with what is working and what isn't.  I use HRD free version and have been using it for about 2 years with my Flex 6700.  It's running very well and I haven't had any trouble.  I'm currently running SmartSDR v1.6.21.  It is extremely stable - at least for me.  Even with the earlier versions of DAX and SmartSDR, it worked pretty well.  The older versions of DAX occasionally had to be restarted or dinked around with but the new version seems to be pretty stable.  I can't remember having any issues that stand out.