485 RFE: FP rejected

I just received 485 RFE for TSC with the following message:

Your fingerprints have been rejected twice by the FBI. Therefore, please submit a five-year certification of good conduct letter. This letter must be written by the law enforcement agency (i.e., local police department) having jurisdication over each residence in the United States that you have held within the past five years.

When I did my fingerprints in August, I was told that my fingerprints were too light to get a good scan, and they only did the best they could and submitted them. Why didn't the CIS ask me to redo the FP? Does anybody here have this kind of RFE? Do I have to personally go to each local PD to get such letters since I lived in multiple states for the past five years? Or I can just send request by mail? Please help me if you have any experience or info getting this kind of certifications. Thanks a lot!