By default, FlutterMail won’t allow subscribers to add their email address to the same list multiple times. To ensure this is not happening, look under the List tab and select the list you would like to edit. Click “Additional and Advanced Settings.” Here you will find a list of checkboxes, two of which are not checked by default:
- Allow duplicate emails to subscribe
- Allow duplicate emails to be sent
Leaving these unchecked ensures that no duplicate email addresses can be added to your lists (or be sent the same campaign instance more than once).
Also, when importing or syncing subscribers there is an option to “Update existing subscribers while importing” under the Advanced Importing Options header.
If the list you are importing does not allow duplicates, checking this option will only modify the existing subscriber record. If left unchecked, the subscriber record will be ignored.
If the list you are importing does allow duplicates, then any existing subscribers being imported will be duplicated into that list.
1. Importing Subscribers