I am a party to the case as the party sending the subpoena and trying to get the information from the Utah resident who I have a contract with and involved in litigation.You didn't answer Quincy's question.
Are you a party to this lawsuit? If so, in what capacity?
Whenever an attorney says he doesn't know, you fire him and get an attorney who does know.
The 3rd party has the information about the Utah resident but is claiming they are governed by California law not Utah law.
This 3rd party company is doing business and making money in Utah. They also have a registered agent in Utah who I believe job is to accept legal documents such as this one.