Originating a call from one country, but setting Caller ID to appear as a different country can cause issues with your call. Local laws often regulate whether a call that originates outside the country is allowed to use a local number. Changing the sender phone number may work fine for calls to some regions and countries, but cause problems in others.
It's possible that a call placed with a spoofed caller ID will work sometimes, or will work for some time and then stop. Calls that do succeed will often have very long call setup times. The cause of this is that while a country may have a law against allowing local caller ID, some carriers, especially smaller, lower quality carriers aren't enforcing the law, perhaps due to misconfiguration.
Long call setup times occur when we or our upstream carriers attempt to deliver a call, bouncing between carriers until we find one that works. Quality issues occur when one of these low-quality carriers accepts the call. When a low-quality carrier does eventually try to deliver the call, the end result could be your call routing to the wrong destination. Call setup failures occur when we cannot find a carrier that is willing to accept the call. Calls that used to work can stop working when the misconfigured carrier fixes their issue.
When a call is accepted, there is no way to ensure that the caller ID you send appears correctly on the user handset. Carriers may strip or replace the caller ID so they can legally deliver it. The misconfigured carrier that accepts the call might be accidentally or purposefully forcing your caller ID to appear as a legal format, changing the number along the way.
When DialSource delivers the call, the call doesn't come "from" the agent, it comes from DialSource, using one of our US-based telephony providers. To have the best chance of connecting the call and the highest quality call, you should not change the caller ID from the DialSource default. Configuring DialSource to send calls in any other way is supported on a best-effort basis only and will almost always cause one of these described issues.