Read through the following topic if you are experiencing Web service callout failed: Unable to find field for type info private LIST<String> class_type_info error.
Web service callout failed: Unable to find field for type info private LIST<String> class_type_info is caused by not having an opt-out link on the Acoustic Campaign email template.
Resolving the problem
To fix the problem, add an opt-out link to your link to your Acoustic Campaign email template.
To complete the opt-out link settings, go to Settings > Organization Settings > Opt-Out > Suppression Settings.
- If you select Opt Out Link Required To Send, at send time a user receives an opt-out error that prevents the email from sending.
- When Opt Out Link Required To Send is not selected, a user might receive a warning at send time, but the email can be sent without an opt-out link.