Cannot send or download mails
All the sudden, the mail function on my MacBook Pro stopped functioning. First, I cannot open the app unless I click "New Viewer Window" on the bar; then when I open the app, I see a message showing, "sending 2 of 2 messages" and last mail in inbox being 5/12/22 (today is 5/17/22). Any leads would be very much appreciated!
MacBook Pro 16″, macOS 12.3