You're getting the following message while you're in the creative previews: 

"Facebook: Your message couldn't be sent because it includes content that other people on Facebook have reported as abusive."

The reason of that is probably because the link you're trying to use as your landing page is blocked by Facebook. The reason of the blockage might vary and it's usually by accident if your website hasn't got a content that's against the FB rules. If you want to check if your link is blocked by FB, you can use this link.
If this is the case, you can get in touch with your CSM or directly with the FB team to request unblocking the link. 

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