We use AuthSMTP.com with fairly link-heavy text. It's often pretty lengthy text, so that might help. Make sure your SPF works. Most of the suggestions here a

We use AuthSMTP.com with fairly link-heavy text. It's often pretty lengthy text, so that might help. Make sure your SPF works. Most of the suggestions here are for campaign software, and that might help-- just use a mail merge feature. Such software often has metrics like bounces, opens, spam-responses built in.