string: Message failed to send inside the standard message send flow

This record has no interpretation yet, so one attached to another record of the same string key is shown for reference. The value may have changed since.

• These messages cover the Schedule Message entry point in the composer and failures while scheduling or sending.

• Companion copy tells desktop users to click the plus button and mobile users to long-press it before choosing Schedule Message.
• The same group distinguishes permission denial, a missing channel, schedule create or update errors, and a general send failure.
• A public scheduled-message send API entry supports the same feature surface.

• It appears in the composer when Scheduled Messages are introduced or when creating, updating, or sending one fails.