Hi Sylvia,
If your iPad is unable to load some certain websites, then I suggest that you clear out the history and cookies from the iPad and try to reload the sites.
To clear your history and cookies from Safari in iOS 8 or later, 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.
Clearing your history, cookies, and browsing data from Safari won't change your AutoFill information.
To visit sites without leaving a history, learn how to turn private browing on or off.
Safari web settings on your iPhone, iPad, and iPod touch
Take care.