Issue re-adding deleted custom domain

I've tried adding a custom domain again after deleting it and i got the following error:

You have already added this custom domain. Select another custom domain or check your project configuration.

You have already added this custom domain. Select another custom domain or check your project configuration.

You have already added this custom domain. Select another custom domain or check your project configuration.

You have already added this custom domain. Select another custom domain or check your project configuration.

Any idea on how to fix this? I've checked the custom domains panel and the domain is not listed there