While it’s very possible that the fungicide caused the dead grass you see, there are a number of other possibilities including cultural variables and diseases. Without knowing the exact cause, it is difficult to suggest a cure because the treatment recommendations are quite different for different problems. The most definitive way to determine what has actually caused the problem would be to send a sample to the Plant Pathology Department at Ohio State. You could take a sample or send it to the Ohio Turfgrass Research Center at 2710 North Star Rd, Columbus, Ohio 43221. It would help them if you could include photos of your yard showing the dead grass as well as the living grass along with samples of both. For more information about submitting a sample you’ll want to read: Sampling | Turfgrass Pathology Program (osu.edu) and Handouts | Turfgrass Pathology Program (osu.edu). You may also find the following websites helpful: Turfgrass 101 by Scott Zanon | BYGL (osu.edu) and Turf_Dis_Chart EXPANDED LAWN Dec. 2 2015.pdf (osu.edu)