Hello everyone, wish you all a wonderful day

So I have this mobile app using Saml method for login. It config just like in Idp Mobile sample. Now when a user press the login button, usually it must go into a screen that ask the user to login using Microsoft account or some such, now it does go it a screen with url "Login(.)microsoftonline(.)com"m then it goes to a redirect screen with text "if you are not redirect click here..." then it goes right back to the login screen. Then an error saying "Request fail with error 403"
If anyone have any suggestion on what happen or how to fix it, it would be very great
*I can't really access or run to debug the code to see what happen, so basically just put up any assumption you guy think it might be causing the error, thank you.
*Some updated is that on one mobile device, the user can't reproduce the error, while the other 2 got the error quite frequently. After restart the app it login as normal but the next time the error happen again