This is simply not respectful.
With online dating (and even dating in general), there is always a small chance for this kind of things happening.
Guys can play games.
The best way to stand in this is to cut contact.
I know it is tough and not easy to understand, but some guys simply lack respect.
Step back and let go.
You can eventually give it one last shot and find out why he did not show up.
However, when this happens twice in a row and he does not apologize or give you a valid reason, it is not a good sign.
Keep your options open and do focus on men who are willing to respect certain limits and boundaries.
Your time is precious and not showing up is a sign of disrespect.
Step back and accept this as a learning experience.
You did everything right.
Learn from it and keep your options open.
If you want to go for it, you can as well send him a clear message telling him that this was plain disrespectful.
You won't let anyone treat you like that.
You will now cut any further contact with him.