Hello @JeniferJ4 ,
Are you having issues with your Preview window displaying? Or are you having issues receiving your test email?
If it's a window display issue, it's likely a connectivity problem that just needs a browser cache clear (just cached images a files, not saved passwords or browsing history).
If it's an issue of test sends now being received, and they're not ending up sent to your junk box, then I'd recommend reaching out to our Deliverability team. I was able to send a test of each campaign you've created to myself, and they all came through right away. Test emails, because they lack authentication, can sometimes trigger email clients since its our system sending an email "from you" to you. This doesn't occur for live sends.
If you need to call into Deliverability, and you're unable to, then let us know and we can submit a callback ticket with a 48-hr turnaround window.