Undoubtedly, among all email services, Gmail is one of the best email services. But, Bad request error 400 on Gmail is still a problem. Gmail error 400 can appear all of sudden in your Gmail account without letting you know. And when this error occurs to any Gmail account then the users fail to send and receive an email to and from contacts. And if it is not handled properly on time then it might prevent the users from login into their Gmail account. A piece of good news is that experts have found the simple tips and tricks to fix Gmail error no 400. For more information, you can reach out to Gmail support.