[Hoa]

Check the mating surface on both to see if there’s any damage or debris. Slight imperfection will cause a leak. If none then reattach again. When you place the rail over the injectors, does it align over all 6 injectors perfectly? If it doesn’t, it may be slightly bent during the initial removal process. You may have to slightly bend it back before reinstall again. During install, jiggle it a little as you hand tighten it to make sure it seats perfectly then torque it down to spec. If it still leak then the only option is to swap the injector with another one and see if the leak follows. If it doesn’t, rail is damage. If it does, injector is damage. I personally wouldn’t replace the seal on the injectors since it haven’t gone through any heat cycle.

Note: during install of the fuel rail, you do have to coat the threads with ATF fluid.