Failed to send icon - Inboxapp API

A red failed to send icon means that specific message was not accepted for delivery on X’s side (usually during an encryption change). The conversation may also show a red dot.

What to do

Message type	Action
Manual message	Resend (delivers with current encryption; old failed copy is removed) or Delete if it’s obsolete
Campaign message	No action — affected campaign messages are rescheduled automatically

Did you lose messages?

No. Messages stay visible in Inboxapp. The icon means the recipient may not have received that one message. If they already replied, they received your outreach. New messages you send go out normally.

Still stuck? Contact support from the app.