Hi Hlaipeng,
To start troubleshooting this issue where you are getting the error that the hotspot login cannot open the page because of too many redirects occurred, I'd like you to please clear the temporary data from Safari on your iPhone. This error message can pop up as the result of connecting to certain Wi-Fi hotspots which require authentication within Safari.
To clear your history and cookies from Safari in iOS 8, tap Settings > Safari > Clear History and Website Data. In iOS 7 or earlier, tap Clear History and tap Clear Cookies and Data.
To clear other stored information from Safari, tap Settings > Safari > Advanced > Website Data > Remove All Website Data.
Safari web settings on your iPhone, iPad, or iPod touch - Apple Support
Take care,
Alex H.