E12017 — SMSSenderReserved

This sender identity is reserved and cannot be used as a sender.

• HTTP status: 422
• Type: validation_error
• Name: SMSSenderReserved

What to do

Choose a different sender; this identity is reserved and cannot be used.

Related

• E12xxx — SMS sending & delivery: every code in this range
• Errors: the full wire contract, status mapping, and error catalog
• Error handling: branching on type and code, validation details, and vendor_code