If your Touché (SE) does not power up anymore when you connect it to a power source, it means that your unit's firmware is corrupt. Most of the times you will be able to recover the unit to a working status by forcing it into Bootloader Mode and flashing the firmware again.

You can force Touché (SE) to switch to Bootloader Mode by pressing both Buttons and the Encoder at the same time when plugging Touché (SE). Its LEDs will become pink. The procedure is shown in this short video.

Once in Bootloader Mode, you have to upload the firmware from Lié again. Please perform the update from the standalone app of Lié instead of using Lié as a plug-in inside your DAW. Please also check that you are using the up-to-date version of Lié, which is accessible inside the "My Downloads & Serials" section of your Expressive E customer account. If you can't find the link to Lié in your customer account, please register your device using the activation code or its serial number (compare Step 1: Registering your Touché and dowloading Lié)

Also take into account all hints given in this article: Fixing problems with updating Touché (SE)'s firmware