Does your device use a multi input? They will usually have a trim level knob which you would adjust to acheive optimum input levels. If that IS what you have and have it turned all the way down and a re feeding a Line Level in and it is still clippling then make sure you have your interface set to accept a Line Level signla (not Instrument or Hi-Z input).
If there is no input trim knob available for that input then you have to do it BEFORE it hits your interface with a mixer or some other external hardware that can attenuate the signal. For examply one of my amps has an output trim on it so I could attach it to a direct in on my interface and just slowly turn up that output trim until I get a good signal. My other amp does NOT have an output trim so something else needs to adjust it before it hits a line input on the interface. So I can run it into my mixer, adjust the input trim on the mixer and/or adjust the output level from the mixer to the interface to give a proper input to the interface and then ultimately to the DAW.
You CANNOT fix a clipping input signal from within the DAW. Once it gets pat your interfac ethat is the signal you are stuck with. If something is clipping inside the DAW that is a different matter and is easily resolved but you want your input to be good before screwing with that stuff.