Once you send out a press release or approach a journalist about a story, they assume you are available for interview at any time so make sure you are. Don’t schedule a dental appointment or a four hour meeting the day you send out a press release. Make sure you are available when the journalist wants to talk to you.
If a journalist wants to set up an interview with you and you can’t do it, more often than not, they won’t ask again. Try to clear your schedule and make sure you are in an environment where you can do an interview.