Hi! Sounds like your problem is a few layers below your application. So if it worked already, and now doesn't. I assume it is either a problem of:

* the hardware

* the USB cable

* the linux driver

* the CODESYS configuration

To exclude the first two, you could test the adapter on another PC or device.

To see if the linux driver works at all, you may test it when CODESYS is not running, with minicom or s.th. similar.

In the CODESYS configuration I can only imagine, that:

* the whole file is corrupted, and can't be read anymore (you should see this in the log)

* the device name is not correct

Good luck!

Cheers,

Ingo