Can't remove default message + date editing

Hi, when someone subscribes to the popup, a message showing “Successfully subscribed” appear in the “after signup” screen. I can’t find that text anywhere, I just want it removed. Please, see screenshot.

Also, how can I change the date format that is being set in the coupon e-mail? It is being show as YYYY-MM-DD and I need it in DD-MM-YYYY.

Thank you! =)
Pedro