iMessage on mac not working properly

Hello to the mac community!

I own an iPod touch and a MacBook pro with mountain lion. iMessage on my iPod touch works perfectly (it always sends, always receive messages seamlessly, and all the messages are in chronological order within the conversation.) On my MacBook pro, it's all the contrary. Messages are sent only 50 percent of the time (I often get "failed to send" with an exclamation point and have to resend it. I may have o do this 3-3 times. Other times it may work in one try) Sometimes I receive messages on my mac after 15 minutes. Also, the messages on my mac are not in chronological order so I often have to look at my iPod to be able to read the conversation.

I checked. Both iPod and mac are on the same email address for iMessage. I do not get why it works perfectly on iPod and it kindda ***** on mac.

Anybody has this problem? Anybody knows how to fix the issue?

Cheers