location = /agendav {
        return 301 https://$host/agendav/;
}

location /agendav/ { # The trailing / is important!
        proxy_pass        http://127.0.0.1:8099/; # The / is important!
        proxy_set_header Connection $http_connection;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Host $host;
        proxy_set_header Authorization "";
}