Kate, Marketo Support ended up asking me for each sales person's name and email address and set up a call with each of them to trouble shoot the issue. I was worried the sales team would be annoyed at having to do this, but they took it in stride (thankfully). The calls only took about 10 minutes each, and the problem was resolved. However, one of the sales guys started having Outlook email issues almost immediately after having the Marketo Sales Insight add-in installed (disappearing emails, emails not sending, etc.). Our tech support could not find an immediate cause and after researching it for a week, found that add-ins like this one can cause these mysterious issues. The add-in was uninstalled, and the email issues immediately cleared up! Our other users have not had this issue, but just wanted to put this one user's experience out there in case you have something similar happen. Hope this helps and good luck!! 🙂