Can't see external HDD when plugged into TC

So I have done research here and haven't found an answer yet. My first problem was the the drive was NTFS so I moved all the data and formatted it to exFAT. Both the PC and macbook pro can read and write to the drive when plugged into each system. When I plug it into the TC it won't show up anywhere. It is an externally powered drive. What have I missed or doing wrong? I want to use this drive as a network drive to keep my itunes library on so 3 systems can access it.