What constitutes a "valid business email", exactly? I entered one, clicked "verify", and was warned to "enter a valid business email." I assure you, I did. What's the trouble?
Having said that i must say our algorithm is deliberately a bit aggressive (so as to prevent spam).
Your email could very well be a false positive. Could you write to support@sess.email from the business email in question. I'll be happy to look into it and whitelist it.