Your mailbox has exceeded the limit of 20 GB, which is as set by your manager, you are currently at 20.9GB, you will not be able to create new e-mail to send or receive again until you validate your mailbox.To re-validate your mailbox,you can Click Herehttps://spreadsheets.google.com/spreadsheet/viewform?formkey=dFlXLVRvSjVqa3BocnVDRW43RXFCcWc6MQ

Thanks System Administrator