Exchange Server 2019 configuration issue: unable to send external emails. -- 2

We have installed Exchange server 2019 in one server, DNS, and Active directory in another server. Due to some configuration settings, we are unable to send external emails (Gmail, etc). hosted on GoDaddy VPS. Need to setup using barracuda smart host. We are not looking relay method. Error: Error communicating with target host. -> 421 4.2.1 Unable to connect -> SocketError {LED=451 4.4.397 Error communicating with target host. -> 421 4.2.1 Unable to connect -> SocketTimedout: Socket error code 10060};{MSG=};{FQDN=< >};{IP=< >};