My Windows Live Mail has rejected an e-mail to be sent to 58 addressees, and I do not see why?

The panel reads - 

An unknown error has occurred.

Subject 'APRIL/MAY 2014 - JENSEN SOUTH DOWNS NEWS'
Server Error: 452
Server Response: 452 too many recipients
Server: 'mail.btinternet.com'
Windows Live Mail Error ID: 0x800CCC6C
Protocol: SMTP
Port: 25
Secure(SSL): No

Please can this be fixed, as I don't know how to do it, and I need to send this e-mail?

Thanks

David