Brand new computer having this issue from the very first time I attempted to visit Hyatt website. I had visited some other stuff prior like my gmail.

Tried deleting only cookies. For whatever reason it instead deleted all history, cookies, and saved passwords on this computer resulting in my having to move all the passwords over yet again so that was an added annoyance. Did not improve Hyatt website experience at all. Still 100% blank.

Currently have old computer sitting here and able to sign into hyatt there no problems so I haven't tried other browsers on this machine as yet. Not really interested in the bother, to be honest. Also don't want to attempt deleting cookies again as it did not work first time but led to me having to transfer all my passwords over yet again which was another bother I didn't need.

Frankly hyatt needs to get their stuff straight as clearly with a thread going back into 2021 this is not new and they have been notified repeatedly as others have mentioned calling them about it in the thread. I ended up booking with Marriott for this particular trip just out of sheer frustration.

Edit to add: Later discovered icognito mode it works fine. Well, except having to open icognito and manually log in. If I didn't have points and free nights already with Hyatt not sure I would have bothered trying.