During configuration of an AudioCodes gateway, a required config for successful TLS negotiation is the use of an NTP server. If you’re running Active Directory domain in your network, your primary time source is the Domain Controller hosting the PDC Operations Master role.

To test NTP is working correctly before hardcoding it into your appliances, you can run the following command:

w32tm /stripchart /computer:<yourNTPsource>

The Stripchart modifier will show a strip chart of the offset between your computer and the NTP source you specified.

Also, for future-proof NTP configuration and to avoid having broken services in case you move PDC role and demote your time source, you can create CNAME records such as ntp.yourdomain.com, or use SRV records like the standard _ntp._udp.yourdomain.com (and point them to _ldap._tcp.pdc._msdcs.yourdomain.com for no manual intervention!).