I used to work at a phone store, however I’m not extremely well versed, but after activating and syncing up whichever provider service to the phone, sometimes certain sites people would go on wouldn’t work, and when me and my manager would trouble shoot we came across some common issues:
I’m not sure which updated software your S8 has because I too am an Apple user, but if you have jellybean, Ice cream sandwich, or marshmallow (these are just software components used when browsing and updates). I know older versions of Marshmallow and jellybeans used to give folks some issues kind of similar to what you’re experiencing, or the page just freezing up completely or only loading half way. Perhaps check to see if you need a system update again?
Maybe try Mozilla as well. If Chrome is doing you good, I’d say keep it.
Other than that, that’s all I can chip in on throwing some help out there. I may be completely off, but hopefully this helps. I also had this issue when I tried signing in on an older S3 model a while ago.