Maria Jhon's Album: Wall Photos

Photo 21 of 59 in Wall Photos

Try to read the blog and execute
the steps properly. The steps are easy to perform and could be helpful for you.
Now, even after executing the steps if you are not able to troubleshoot this
issue, you can take help from the executive team at Gmail Customer Service . 

https://contactforhelpblog.wordpress.com/2019/07/16/eliminating-gmail-bad-error-request-400-like-a-pro/