Apple Mach-O Linker (ld) Error Group

Hi Guys, Im using Xcode 8.3, Unity 5.6. I was always using unity 5.5 and I publised my game to the apple app store. Since Unity Ads werent shwoing up on the build on the app store, i looked online and found out that i had to upgrade it to unity 5.6. I upgraded and then built it and laucned it on Xcode 8.3. But now im getting a error that isnt allowing me to build it. Error: Apple Mach-O Linker (ld) Error Group clang: error: linker command failed with exit code 1 (use -v to see invocation) Any Help would be deeply appreciated, Thanks in Advance!