Prod | Text document is showing error in Preview Form

Steps:

1. Open Send Forms.
2. Select Text Template.
3. Provide mail id & Subject
4. Now click on Preview Form.
5. Observed that an error message is coming.
6. Now try with new mail id & click on preview & send the form.
7. Again send the text template with the above used new mail id.
8. Observed that an error message will again appear. 

Expected Result: Error message shouldn't come in the Preview form.