Exclamation points are added in newsletter (not on the website)

Hi again,

When sending a test newsletter or a normal newsletter to a testgroup it shows some exclamation points in the newsletter.
Because of that, a table is not displayed correct, text is missing and an image is not being displayed.

Please see the image:

However the newsletter on the website is displaying perfectly!

Support access is ACTIVE until 24 July 2015 16:15

Greetings,
Age