使用新电子邮件模板时突然出现高电子邮件跳出率

We have been using iContact for Salesforce to send our company's mass emails for a couple years. We typically have low bounce rates (1-2%) and are consistently sending large numbers of emails (30,000 - 40,000 total sends per month, spread across 10-20 different emails).We have been using iContact for Salesforce to s