Why won't my email or phone script allow preview?

If you try to preview an email or phone script and it give an error such as HTTP ERROR 500, this can mean there is an error the HTML code 

This usually means that there are brackets of some type that are applied incorrectly in your email. Look for  things like <a href="{{{unsubscribe_link}}}"   as the extra brackets would prevent a link like this from working. Also, Brackets like { } without the use of personalization codes will cause this error. 

Errors in the Phone Script can also prevent a dial session from starting. 

If you use a script and try to start a dial session and it does not start, try without the script and if it will start, you will need to check the script.