facebook login error

Hello I was logged out of my facebook app few days ago. I tried to log back in but it keeps giving me an error message. to try to log in again . i looked it up and did all the steps. reset location and privacy . I also reset my entire phone a few times nd still not working . I am able to login to facebook thru my labtop or my internet browser on my phone. I have iphone X . Can anyone help ? thanks