CSS error on new order notification

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Hello,
After upgrading whmcs its giving CSS error in order notification. I tried to remove the CSS from General setting > mail >  but still I am getting this error. Can someone guide me how to fix?

.ExternalClass,.ExternalClass div,.ExternalClass font,.ExternalClass p,.ExternalClass span,.ExternalClass td,h1,img{line-height:100%}h1,h2{display:block;font-family:Helvetica;font-style:normal;font-weight:700}#outlook a{padding:0}.ExternalClass,.ReadMsgBody{width:100%}a,blockquote,body,li,p,table,td{-webkit-text-size-adjust:100%;-ms-text-size-adjust:100%}table,td{mso-table-lspace:0;mso-table-rspace:0}img{-ms-interpolation-mode:bicubic;border:0;height:auto;outline:0;text-decoration:none}table{border-collapse:collapse!important}#bodyCell,#portant}.headerContent{font-size:20px!important;line-height:125%!important}.footerContent{font-size:14px!important;line-height:115%!important}.footerContent a{display:block!important}#footerImage{float:none;padding:0 0 20px 0}.hide-mobile{display:none;}}table.grid-block,table.grid-block table,table.grid-block td{margin:0;padding:0;border:0;background-color:inherit}table.grid-block-inner{background-color:#efefef;}@media only screen and (max-width: 640px){td[class=rid-block"] table{width:100%}td[class=rid-block"] .spacer{display:none}td[class=rid-block"] .row-nopadding{padding:0!important}td[class=rid-block"] .section{display:block;float:left;height:auto;padding:10px 20px;margin-bottom:8px;-moz-box-sizing:border-box;-webkit-box-sizing:border-box;box-sizing:border-box;width:100%}}