While creating email in Eloqua design editor, I'm getting the responsive concern warning?

At the time of email creation, I'm getting the following warnings

Responsive Concerns

You have at least one table tag in your content that may not be responsive

You have at least one image that is not responsive

You have at least one text string or URL that is >25 characters and is not responsive

After chosen the header and footer, I got the above warning. But the responsive of the email in all clients looks good.

Please help me to understand why this warning message are populated?

Thanks,

Bharathi