This is a problem commonly seen in Safari for iOS when settings for acceptance of cookies is too strict. Cookies are required to log in to most websites.
To enable cookies in iOS Safari:
- Go to the Home screen by pressing the Home button or by unlocking your device.
- Select the Settings icon.
- Select Safari from the Settings menu.
- Select Accept Cookies from the Safari menu.
- Select From visited from the Accept Cookies menu.
- Press the Home button to return the home screen.
- Select the Safari icon to return to Safari.
- Before the cookie settings change will take effect, Safari must restart. To restart Safari: Press Home twice to bring up open apps, find Safari and press and hold the icon, then select the red symbol near the top left of the icon.
- Select the Safari icon to return to Safari.