linker error because it couldnot red some missing symbols, This could be due to several reasons:

1- Missing frame works or files: go to build phases to make sure it linked with frameworks and libraries make sure yoy framwork listed on linked files in your target build settings.

2- make sure if you have objc-c files or biriding files in corrct briging header

3- Check your Other Linker Flags in build sttings may files in correct like obj-c files.