Unfortunately Inventor does not tell you where the conflict is, you have to try to work it out for yourself. If you use 'assembly view' in the model browser the constraints are in a drop down for each part in the model which narrows the choice down a bit but remember that, if a part is constrained to a 2nd part, the conflict can be between that 2nd part & a 3rd part.

Inventor is not very helpful in this.