Inbox has been showing 1 even though there are no new messages

Hi Team,

Advance Merry Christmas and a happy new year. Sorry to bother you during the festive season. You can enjoy the holidays and reply to me when you are free, no rush.

Wanted to let you know that my Inbox has been showing 1 even though there are no new messages. It's been a while it is like this. I tried clearing cache and stuff but didn't help.

Below is a screengrab of the issue,

Thanks in advance!

Dixon Selvan