Problem with SSO Login on only Iphone Mobile login

I'm having an issue with my embed paged w SSO login not working through my IPhone. It goes through the login process, but then just redirects back to the login page. This problem exists when using any browser on my Iphone(Tested on Chrome and Safari).  Logins work normally on Android and Desktop, so it seems to be an Iphone specific issue. Also, normal account signup on Iphone works, but does not keep the user logged in when navigating through pages on the site.

Has anyone else experienced this problem and/or have any suggestions for a potential fix. The embed login in question is at  feel free to test on your end and lmk if it reproduces the problem