This will depend on the browser you use.
- Open Chrome from your phone’s home screen.
- Press the menu icon (three vertical dots) in top right corner of the screen.
- Tap History on the menu that opens, and then tap Clear browsing data....
- Adjust the time range to cover the period when the problem started.
- Make sure Cookies and site data is selected.
- Tap Clear data.
- Open the Settings app on your phone.
- Select Safari from the list of apps.
- Tap the link near the bottom that says Clear History and Website Data.
If your phone uses a different default browser, please check the browser's website for instructions on how to clear your browser cache and cookies.