Yes, however only the trunk needs to change the codec, the server will convert this for you. You do not need to change any codecs except your truck and on your carrier.
Telnyx had the same issue, on our account on the backend they temporarily disabled inbound routing from one of their carriers on the PSTN because of these issues and it worked. This was fairly recent.
Be sure each device is using a well maintained DNS provider, your current DNS provider could be the culprit. If you have an SBC, you will either need to reboot it or shutdown your old 3CX Instance.
https://www.3cx.com/community/threads/delete-instance-hosted-by-3cx.75573/
On this note, if you assign the same license to another server, it will deactivate the license off the old server after it has changed the IP addressed assigned to the FQDN.
Your 3CX FQDN is tied to a single license, if you used your 3CX license your 3CX FQDN will be used unless specified that you are using your own. 3CX will not mark licensing provisioning as complete until the FQDN has propagated the new IP address assigned to the new instance.
Need to become a partner again to request PIDF-LO as a feature. It will save both 3CX and the configurator to reduce headaches and implementation times. They might have to anyways for soft phones.
RAY BAUM’s Act requires that 911 calls from multi-line telephone systems (MLTS) include a “dispatchable location.” According to the FCC, that is “a location delivered to the PSAP with a 911 call that consists of the validated street address of the calling party, plus additional information such...
Also, on your sip provider. Insure your sip provider has RTP auto adjust disabled on your fax number and that they have T.38 enabled with re-invite initiates at customer end.
It does work,
Make sure you use "admin" as your SSH login.
If you created a .pem file, you will need to use PowerShell.
open PowerShell and modify as needed, replace the "example.com" with your instances information. You can also use the "Public IPv4 DNS" it will look something like this...