i have a server wich gif me prblom with sending more than 50 iemail one time

I got this massege

Network Error (tcp_error)

A communication error occurred: ""
The Web Server may be down, too busy, or experiencing other problems preventing it from responding to requests. You may wish to try again at a later time.

For assistance, contact your network support team
i want to be sending more thin 1000 email one time

I had this on anather server one of my frined solve it for me

can someone help me to solve it