When attempting to add an email to the contents of an email in Email Marketing in Online Express, the error, Please specify a valid URL, will appear.
UPDATE: This has been resolved with the 10/24/16 release of Online Express. If you are still experiencing this behavior, please manually recreate your email.
In the meantime, we can accomplish this by doing the following:
1. Navigate to Email marketing in Online Express 2. Click on an email draft or click Create a new email 3. In the content editor, click “Edit” in the area you want to add the hyperlink 4. Highlight the text you want to use for the hyperlink 5. Click the Insert Hyperlink icon 6. Click the Email address option in the Create link window 7. In the Email address field, type mailto:[the desired email address] 8. Click Apply 9. Click Apply 10. Make any other desired changes 11. Click Save & continue