To resolve this issue, navigate to Setup ->Session Settings
Under Trusted Domains for Inline Frames, click Add Domain
Copy the current url from your browser address bar
Keep only the domain part which ends with force.comarrow-up-right
Ensure to remove the https://
Paste this domain in the Domain field and the iFrame Type should be visualforce
Save
The Email Preview page should now load correctly.
Last updated 9 months ago
