PHPbb Registration and Activation Email Problem

Hello there, I'm using phbb3.3 and my register activation type is from adminastor.When users register to forum Board can't send the registration email also when i activate the users nickname board can't send the activation email.But board can send subscription,announcement,forgot password and etc. emails. I'm using domain mail from cpanel like **@mydomain.com When forum send Registration and Activation Email i get a mail like this: This message was created automatically by mail delivery software. A message that you sent could not be delivered to one or more of its recipients. This is a permanent error. The following address(es) failed: ***@gmail.com host n1nlshrout-v02.shr.prod.ams1.secureserver.net [***.***.***.***] SMTP error from remote mail server after end of data: 552 5.2.0 LucDjuaS0IovO :: CPANEL :: Message rejected for spam or virus content :: Please include this entire message when contacting support :: v=2.3 cv=eqmhMbhX c=1 sm=1 tr=0 p=t_0pBC7S30JegIlTARkA:9 a=gSwbFB+04S26Rs2Viqn6JA==:117 a=9+rZDBEiDlHhcck0kWbJtElFXBc=:19 a=dLZJa+xiwSxG16/P+YVxDGlgEgI=:19 a=IkcTkHD0fZMA:10 a=cl8xLZFz6L8A:10 a=5KLPUuaC_9wA:10 a=M51BFTxLslgA:10 a=jJxKW8Ag-pUA:10 a=3oeywE6IAAAA:8 a=QEXdDO2ut3YA:10 a=u5hwJhHMIZzzwb98Ab6k:22 a=pHzHmUro8NiASowvMSCR:22 a=nt3jZW36AmriUCFCBwmW:22 :: 100.00 Reporting-MTA: dns; n3plcpnl0092.prod.ams3.secureserver.net Action: failed Final-Recipient: rfc822;*****@gmail.com Status: 5.0.0 Remote-MTA: dns; n1nlshrout-v02.shr.prod.ams1.secureserver.net Diagnostic-Code: smtp; 552 5.2.0 LucDjuaS0IovO :: CPANEL :: Message rejected for spam or virus content :: Please include this entire message when contacting support :: v=2.3 cv=eqmhMbhX c=1 sm=1 tr=0 p=t_0pBC7S30JegIlTARkA:9 a=gSwbFB+04S26Rs2Viqn6JA==:117 a=9+rZDBEiDlHhcck0kWbJtElFXBc=:19 a=dLZJa+xiwSxG16/P+YVxDGlgEgI=:19 a=IkcTkHD0fZMA:10 a=cl8xLZFz6L8A:10 a=5KLPUuaC_9wA:10 a=M51BFTxLslgA:10 a=jJxKW8Ag-pUA:10 a=3oeywE6IAAAA:8 a=QEXdDO2ut3YA:10 a=u5hwJhHMIZzzwb98Ab6k:22 a=pHzHmUro8NiASowvMSCR:22 a=nt3jZW36AmriUCFCBwmW:22 :: 100.00