@asiangal555,
What exactly is your relationship with this guy?
If you just met or are getting to know each other, then this guy might just not be sure if he wants to do things together with you again. Also how long have you not been receiving emails?
If your relationship with him is good or you know each other well, then maybe he's possibly trying to figure out how he feels about you, or even how you feel about him.
He also might just be busy, for both situations. Or he's just deciding for a long time.
Anyways, see if he's ever acting nervous or weird around you, or he cares about your opinions.