Paxton is an elected official. Which makes his conduct more egregious. It is one thing for a private citizen to duck a process server. It is quite another for a public official to do the same.
Moreover, Paxton is an attorney. Ducking a process server would seem to me to be conduct unbecoming an officer of the court. I think at the very least a public reprimand is appropriate.
In any event, the Federal Judge acted appropriately. Paxton is a public official and he knew damn well that he was being subpoenaed to testify. The court need not tolerate an attempt to evade a subpoena, particularly when the intended recipient is an elected official.