iCloud says Mail is using 1.3GB but all the Mail folders including Trash and Junk are empty
I have deleted all the mails from my iCloud but it still says that 1.3GB is being used by Mail.
I have checked all the folders including trash and junk but there is no mail in there.
What is the solution to this? How can I get rid of that hidden 1.3GB?
MacBook Pro 15″, macOS 11.6