Looping Messagebox

Hi All,

I'm hoping you can help, I currently have the below code which works well:

Please Login or Register  to view this content.

However, I've been trying to add a Else messagebox because if the textbox 1 and textbox2 do not match I'd like the user to know so they understand the value they input was incorrect but if I do it keeps looping. How can I fix this?

Thanks.

maybe something like this

Please Login or Register  to view this content.