Internal error has occured - Object reference is not defined to an object session

Dear Support team,

I use your ETS 5 pro tool (latest version) in order to configure and maintain a single project : my own house.

Last time I used your tool, a few month ago, everything was fine.

Today, I'm having a issue with a device and I wanted to tweek a few parameters to fix it.

I went on my device (Topology), changed a parameter, then right click on the device on the "topology zone" => Download => partial download. Then, I have a regular warning message regarding my adresses but I disgard it.

Usually, the download process to the device starts and it works well.

But today, the download process didn't start. Instead, I got an error (see printscreen). I translate it to : "Internal error has occured - Object reference is not defined to an object session".

This error completely crashes ETS. I have to kill the process through Windows Task Manager and start ETS again.

This is the first time I got this error. Nothing changed in my configuration. My KNX - IP bridge works well as I'm able to switch on / off different devices through my cell phone.

If I try to change a parameter on another KNX device, I still got the error and ETS crashes but before crashing, the download process seems to happen anyway (I see the bar completion of the device filling in).

Can you help me solve this issue, please ?

Thank you very much.

Best,

Pierre Antoine CHAPELLE