Macro Button in Excel spreadsheet (from a client) not working for some people

I work at a firm that is using Excel 2010.

We received a spreadsheet from a client. This spreadsheet has a macro button in it that generates an email based on the filled out form.
It works perfectly for me. However, for the group of users that need it, the macro button does nothing. I click it, and it generates an email properly. They click it, and nothing happens at all.

I went thru and checked the security settings in the trust center, and we match up perfectly.

Does anyone have any suggestions as to what might be blocking it for them?

I don't disagree. I am just having problems figuring out what else could be affecting it.