Hello @MrMaster
Please note that the TTL for the FQDN on Standard and PRO licences is 6 hours. The TTL for Enterprise licences however is 5 minutes as it is designed for failover. You could upgrade your licence to Enterprise to have the TTL of the FQDN reduced to 5 minutes.
Founded in 2005, when VoIP was an emerging technology, 3CX has gone on to establish itself as a global leader in business communications.