With many discussing this issue on various social media platforms, Google has gone onto acknowledging this glitch and setting forth its engineers to investigate on having it resolved at the earliest.
- Users reporting the issue has brought Gmail acknowledging it and agreeing to provide timely updates until its resolution
As per the statement made by them on their G Suite Status Dashboard
The updates on the same shall be made by Google until its resolution.
So all we can hope at the moment is the issue gets resolved at the earliest and one is able to send their mails, upload their attachments, etc, without any hassle ASAP!