There are two main reasons this could happen:

1.  You did something to spook her.  Think hard about everything you said or wrote to her.  Something maybe went wrong.

Did she see your car?  Do you drive a Ford Crown Vic?  Things like that sometimes set a gal off.

2.  Something came up for her right away.  It could have been some kind of family emergency or similar situation.  You'll never know.

In any case, shrug it off and her too.  Go on to the next date.

If you follow procedures, you'll do fine.

The only time I went to someone's home it was in Manhattan. I don't think I'd do it in a suburban type setting.

Most likely a case of "sh*t happens."  Providers are real people with a life outside of the biz too.  Something probably came up at the last minute with a family member.

You didn't say but did you confirm earlier that day before making the 45 minute drive?

Frankly, if she knew you were on your way & she had your number, she should have called you back, if possible.  A lot of Ifs in there.

My guess is "Life Happened".  My guess is it was nothing you did since you were good to go when you started your trip.  
Unless something you said when you made the second call upset her, I can not imagine anything else.

If you have e-mail contact, I might send a super polite note just to say "how disappointed you were."  Otherwise, just move on.  
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