If you're seeing client messages marked as Declined or Not_Opted_In, it's likely that the client hasn’t opted in to receive manually issued messages from your account.
This behavior is tied to a platform update introduced in Release 8.19 (October 22, 2024), which added new opt-in requirements for invitation messaging to comply with email and SMS messaging standards.
What Changed?
With this update, new "Allow Messages" checkboxes were added in two places:
- On the Your Information page during appointment scheduling
- In the My Profile section of the client’s scheduler
These checkboxes are enabled by default on the Your Information page, but clients can choose to deselect them during booking. If they do, this opts them out of receiving any non-essential emails not directly related to appointments or manually sent invitation templates.
Choosing to edit an appointment email before sending it from the Backoffice would also cause an email to show as Declined for a client that has opted out of this messaging due to the nature of that customization. 
Client Opt-In Requirement
- To receive non-essential emails and SMS messages, clients must have the Allow Messages checkboxes enabled—either updated when booking another appointment or later by editing their profile. If these checkboxes are not selected, any manual messaging sent to that client will be marked as Declined or Not_Opted_In, and won’t be delivered.
Staff Limitations
- Staff cannot change a client’s messaging preferences from the Backoffice. Clients must log into their scheduler profile and update this setting themselves.
How to Fix This
Because the messaging opt-in settings can only be set by the client themselves, you will need to allow your clients to log in on your booking sites to change those settings. Read more about updating your client login settings.
If a message wasn’t delivered because a client was not opted in:
- Have the client log in to their scheduler account
- Navigate to My Account > My Profile
- Edit > Enable the Allow Messages checkboxes > Save
- Once enabled on their profile, you can resend any previously declined messages
