Iphone Music App does not synchronize due to connection error with NAS

Recently, I gave my NAS a fixed IP address, as for some reason after temporarily disconnecting, it chose another one and my photography software kept looking for the wrong address in search of its database. But now that I fixed that, all of a sudden my iPhone keeps referring to the address I had just gotten rid of in the first place to solve the other issue. I wasn't even aware that it was apparently directly connecting to that database instead of through the Music App on my desktop... How can I have my iPhone connect to the correct address?