Not Receiving All E mail From Clients - PLEASE HELP!!

Not Receiving All E mail From Clients - PLEASE HELP!!

Hi, 

I have checked the MX records to ensure they are pointed appropriately and they seem to be correct, however, I am not receiving e mails from some clients. It's not connected to one type either. Some gmail addresses are coming through and come are not. Some people's came through this morning and now are receivng and error message. I have not touch the MX records since last night.  I did play around with the MX info last night and remember it saying "It may take up to 24 hours to sync with all servers". I am hoping that that may be the case... But it's so odd that some gmail addresses are going through and some are not. AND that some were working this morning and now they are not. 

For example, betsy.resnick@gmail.com continues to receive this error message: "-----Original Message-----
From: Mail Delivery Subsystem [mailto:mailer-daemon@googlemail.com]
Sent: Tuesday, February 25, 2014 1:07 PM
To: Betsy.Resnick@gmail.com
Subject: Delivery Status Notification (Failure)

Delivery to the following recipient failed permanently:

      kelly@resnicklawoffices.com

Technical details of permanent failure:
Google tried to deliver your message, but it was rejected by the server for the recipient domain resnicklawoffices.com by mx.resnicklawoffices.com. [66.96.142.52].

The error that the other server returned was:
550 5.1.1 < kelly@resnicklawoffices.com> recipient rejected" 

Brandon.resnick@wellsfargo.com has this error message a couple minutes ago but was able to get through this morning:   
"Delivery has failed to these recipients or groups:
 
kelly@resnicklawoffices.com
The e-mail address you entered couldn't be found. Please check the recipient's e-mail address and try to resend the message. If the problem continues, please contact your helpdesk.

 
The following organization rejected your message: mx.resnicklawoffices.com."

I am concerned because this is my e mail address for my law firm. I am the main point of contact as the owner and managing attorney. My clients are worried that I have left them. I want to thank you in advance for looking into this. 

Contact me at: kresnickesq@gmail.com incase my zoho doesn't work. 

Thank you.