Disclaimer:
Heymarket makes it easy to send messages to a list.
Once you've created your list, navigate to it and select Compose Message where you can draft your own message or apply a template. You can send a message immediately or schedule it later. See the above video for a step-by-step guide on sending messages to a list.
To bulk opt out contacts with failed messages:
Navigate to the report for the sent message (e.g., from the Broadcasts, Campaigns, or Lists section).
Click the Failed tab in the Contacts section to filter for contacts whose messages failed to deliver.
Select the contacts you want to opt out using the checkboxes. You can select individual contacts or use the top checkbox to select all. Click Opt-Out SMS in the action bar that appears above the contact list.
The selected contacts will be marked as Opted-Out or Deleted and will no longer receive messages from your team. As with any opted-out contact, their status can be viewed in the contact pane.
This is a faster alternative to opting out contacts one by one from the contact pane, especially after a large send where multiple messages failed due to invalid or unreachable numbers.
Note: The keywords for opt-out and opt-in are case insensitive. Also, any leading or trailing spaces are ignored.