Applies to: Original-charger Iridium 9555 record, using H2UG1801, NOV18. The cover says “Iridium 9555 Satellite Phone” with the subtitle “Iridium 9555A User Manual”. This guide follows that exact document’s printed pages 89, 94–95 and 102–108, not the separate 9555 USB-C edition 770-00003B, Extreme 9575 or PTT. Historical instructions do not establish current airtime eligibility.
Work through these checks
Locate the original attempt’s final stage
The manual’s Drafts workflow separates editing, choosing Send, selecting numbers in Send To, and the final Send. Compare those stages with what actually happened earlier. An item saved as a draft has not, just by being saved, completed this workflow. Read the existing list and original response only; do not open an edit/send sequence to reproduce the fault.
What the result means: Report an incomplete local preparation separately from an attempted network send. If the final send was already attempted, preserve its exact error and time; this manual section does not define an Outbox status as proof of recipient delivery.
Read the SIM-message storage warning
For this manual, messages are stored on the SIM and a flashing message indicator means that storage is full. The Inbox section says a full SIM-message store cannot store a message for later retrieval. Record whether the message indicator is flashing and distinguish it from a received-message alert or the normal network status light. Preserve the messages; do not use Delete or Delete All to diagnose this.
What the result means: A full-storage indication identifies a local message-retention problem; it does not by itself prove a satellite-network outage or explain every outbound failure. Have the owner/provider arrange any needed preservation and storage management separately from this read-only review.
Compare the existing messaging settings
Read Messages → Settings without saving another value. H2UG1801 says the Iridium service centre is used by default if no number is explicitly configured. Expiry Period limits how long an undelivered message waits: one, two or four hours, one or two days, or one week. Delivery Reports has its own OFF/ON choice. Record these separately and ask the airtime provider to confirm any existing service-centre override; do not copy the illustrated number as a fix.
What the result means: An unset override may be normal because the manual specifies a default. OFF means reporting is disabled, not a failed delivery. The expiry setting is not a delivery receipt. These observations give the provider a bounded configuration report without changing the evidence or creating further SMS charges.
When to stop and get help
Do not create a test SMS, resend a saved message, delete messages, replace the SIM, alter the service centre or expiry/report settings, or reset the phone for this review. Preserve evidence for the airtime provider if it remains unresolved. Do not use SOS or emergency recipients as tests.
What to tell support
Privately give the airtime provider the manual identifier, attempt time, exact response, registration, steady/flashing message indicator, whether the item is a draft, and current service-centre, expiry and reporting observations. Preserve message contents and recipients; disclose them only through the provider’s authorised private support process when needed.
Original troubleshooting guidance based on the official sources below. Menu names can change. This is an independent guide, not a manufacturer service bulletin or a bench-tested repair.