When we use HTML to create an email, there is an error that appears stating that Marketo is unable to load the HTML code. Is there something we're not doing correctly?
It would be helpful if you can share error snapshots and/or more details on the error. Do you see this while editing the email, or while approving the draft, or while trying to edit an approved email (cannot load email error)? Also, you may already know this but just for reference Marketo requires the emails to be created in the syntax that it identifies with for creating the email modules/editable components/elements.
Can you post the HTML? Tell us the error?
We're completely blind here.