Pop up stops working on same page after being clicked once

Hello,

if a user clicks my pop up (I'm using one to show a message with call to action to take user to a different website) it works great. If they close the pop up window then click the link again, the pop up doesn't work.

I know it's not a scenario that will crop up too often but I need to fix it as the client has been asking.

I assume it no longer works because the cache has that pop up as already viewed maybe?

How can I fix this please?

Thanks!