DSLRequestProcessingException error occurring while executing services for mail notifications

[AP_10343008]

Iam getting this error in production which is stopping mail notification.

error: 

Service1: error is JavaException: com.thingworx.dsl.exceptions.DSLRequestProcessingException: Execution error in service script [Service2] :: Not authorized for ServiceInvoke on CreateValues in MailFileRepositoryAttachments

In Thing, Service2 is called inside Service1.

This error is occurring only in production but working fine in dev servers.

How to fix this?

[cmorfin · Accepted solution]

This error refers to a permission issue.
If you access the Thing MailFileRepositoryAttachments then Permission > Runtime
Add a service Execute permission on either all services (top table) or specific to service CreateValues (bottom part of the page) to the user executing your services.