Mail app icon not showing number of unread emails for gmail account

I noticed the mail app icon is only showing number of unread messages for my ICloud acct but isn’t showing number of unread messages for my gmail acct. yes, the badges for gmail under notifications is set to “ON.” It used to show the total number of unread messages between both accounts, but now only is showing unread ICloud messages and nothing from gmail. Again, gmail notifications have badges set to on. What could be wrong, and why is this happening all of a sudden? Thanks.