Sometimes when you try to add a contact created in Autopilot to Pipedrive, Pipedrive will return an error which means Autopilot can't complete the sync. When this occurs, instead of being added to the dedicated Pipedrive Contacts list (which would indicate they were successfully synced to Pipedrive) they will instead be added to the "Pipedrive Contacts Error" list.
When you view the contact in Autopilot you will see a contact Activity Feed item that will contain the error that Pipedrive returned, for example:
Once you have addressed the cause of the error, you can click the "Retry sync" link shown above to re-attempt the sync to Pipedrive. If it is successful you will see a new Activity Feed item indicating that the contact has been successfully synced to Pipedrive.
The contact will then be removed from the error list and automatically added to the Pipedrive Contacts list.
If you have multiple contacts that you need to retry, you can mass select them and manually add them to the Pipedrive Contacts list. In cases such as these you may prefer to view recent errors in the Status Log to get an overview of errors that you need to address, rather than viewing individual errors in each contact's Activity Feed.
If you decide that you do not wish to pursue adding a contact which has returned an error to Pipedrive, you can manually remove them from the Pipedrive errors list.