Images in emails not previewing

Images in emails not previewing

Hi

When I import my campaign HTML email into ZOHO some of the image previews are broken. If I re-import the email then it might fix the broken ones but others are not working. This occurs both in the ZOHO email preview window and in test emails. I know my content is ok as I've used it before and the fact that the problem is intermittent confirms this.

What's going on?