Hi @Aquarellabrazil !
Thanks for the screenshot. The meta tag code you entered looks to be in the correct place, so at this point it might be worth trying using the DNS verification method, as outlined in Facebook’s help doc. There, you’ll also find a video that will walk you through the process of editing your DNS settings.
If you’re still experiencing the same issue after following those steps, I suggest going through Facebook’s appeal process. This will let Facebook and Instagram know that you are using a custom domain and should resolve the issue! Keep in mind that it may not be immediate, as Facebook will need to review your submission.
Best of luck on those next steps!