Small fix on No Contact record issue

We have an issue with No Contact Record error on an installed application in SalesForce. When we try to send an email to a non-contact email it will give an error: ERROR:[[[[ERROR: Email - SDEMAIL CONTROLLER LINE:3089 USER:[user] ERROR:Error inserting No Contact Record: Insert failed. First exception on row 0; first error: DUPLICATE_VALUE, duplicate value found: ContactUniqueConstraint__c duplicates value on record with id: 0032p00002ufLsh: [] Are there validation rules, triggers, required fields, etc. on the Contact object in this org that might have caused this to occur? You can use add &useExistingNoContactRecord=true to your S-Docs button to resolve this, though that will prevent future emails from being saved in the Activity History related list STACK:(SDOC)]]]] STACK:(SDOC) We've been in touch with S-docs and they supplied us with a small change in an Apex Trigger which we need to implement.