How to resolve HTTP Status 400 Bad Request error in Rakuten

You may see this error when you login to Rakuten, and can not proceed to next step.
I will explain the reason and how to resolve it.

Reason of 400 Bad Request

Browser have a function called "Cookie" which contains customer's information.
Web service store their data for various kind of purpose.
ex) Session for login state, search condition and so on.

Rakuten store many cookies, and Rakuten is a gigantic service and there are many services under Rakuten try to store cookies under "rakuten.co.jp" domain.
It cause cookie data for Rakuten domain getting bigger and bigger.

If you visit to a website having big cookie data, the web service(server) crash by it and cause this error.

In most case, this is the reason If you see this 400 Bad Request error.

How to resolve 400 Bad Request

iPhone Safari

There are 2 ways.

• Delete browser's whole history and cache data with Setting app.
• Open a tab using Private Browse.

Android Google Chrome

There are 2 ways.

• Delete browser's whole history and cache data in setting menu.
• Open a tab using Secret Tab.

PC Google Chrome

There are 2 ways.

• Delete browser's whole history and cache data in setting menu.
• Open a tab using Secret Window.