If you're already editing your campaign, you can review your campaign summary by clicking on the Send step in the top right of the screen.
If you've closed your campaign, then select Campaigns from the navigation bar and your campaigns list is displayed.
Click on the Summary icon alongside the appropriate campaign to display your campaign summary.
The 'Summary' page displays your campaign details, HTML size, word count, image sizes and links within both the HTML and plain text versions of your campaign, and, lastly, details about your testing.
Sometimes, although a link is valid, we can't validate it because the server takes too long to return its status.
If any hyperlinks are not validated, send yourself a test send of your campaign and check that those links work.HTML size
If the HTML size of your campaign is too large, Gmail will clip your campaign, but you can take steps to reduce the HTML size.
Use the Edit icon alongside the appropriate section to make any changes.