As of now Canon EOS T6i is not supported for tethered shooting in Lightroom.
Please check the article for the list of tethered shooting camera : https://helpx.adobe.com/lightroom/kb/tethered-camera-support.html
Please let us know if it helps.
Any ETA on when you guys will be adding support? I love Lightroom!!
I understand, however there is no ETA as of now.