thanks for your reply. the problem is not the gate at the castle but the door after the gate. i no longer have any saves that go back before i met serana. It appears to me that the door just does not have an active hotspot on it that allows it to open, when clicking on the the door message. i will try attacking serana and the door guard in various ways and see if that helps. If all else fails i will just continue the game without completing the dawnguard quest, and keep serana with me until,or if, she decides to leave me. i hope serana's clan of vampires are not the ones responsible for killing the various holds citizens, or that could cause some problems eventually. thanks again for your help. i will let you know if the attack options work. not using any mods. as far as i know i have no way of entering any console commands on the ps4, so those other posted messages, re:console command fixes, can not work for me.