Program an Arduino Uno with an Atmel ICE When I connected my atmel ice to my arduino uno everything went okay.
Then I tried debugWIRE and since then I can't connect to my ATMEGA328p.
I get the error 
Failed to enter programming mode. ispEnterProgMode: Error status received: Got 0xc0, expected 0x00 (Command has failed to execute on the tool)
I think one of the fuse bits is wrong but can't connect to the ATMEGA328p to change them. Does anyone have a idea what to do?
Your Ardunino is stuck in debugWIRE (The debug wire fuse is set). Here is a tutorial on how to get it back to programming mode.

In the tutorial I am using the AVR Dragon with AS6, but the process is the same with Atmel ICE and AS7.

You have to be in Debug Mode to disable debugWIRE. While in debug, Click Debug>Disable Debug Wire and Close.