Is my SIM dead? How to tell in five minutes

What your phone is actually telling you

Two very different failures produce nearly the same screen, at different layers.

The first question is whether your phone can read the card at all. A SIM, physical or embedded, is a small secure-element smartcard. The phone powers it, reads its ICCID — the serial number printed on a physical card — and pulls the IMSI, the subscriber identity your carrier assigned to your line. When that conversation fails, the phone says so in device language: “No SIM card”, “Insert SIM”, an empty slot in settings, no serial number anywhere. That branch genuinely is hardware, and it is the branch Verizon’s troubleshooter describes when it lists a card that is “cracked, worn, split, etc.”, dirty or corroded contacts, debris in the slot, moisture, or a card put in the wrong way around.

The second question is separate and far more common: will the network accept the identity the card handed over? Your phone asks to attach, presents its identity, answers a cryptographic challenge, and the network either admits it or refuses. When it refuses, it does not send prose. It sends a numbered reject cause, defined in a public standard, 3GPP TS 24.008. That number, not the wording your phone wraps around it, is the diagnosis.

Cause #2 is the one almost everybody misreads. The standard defines it as “IMSI unknown in HLR”, “sent to the MS if the MS is not known (registered) in the HLR”. The HLR is the subscriber database. Your card worked, it produced an identity, and the network found no record of it — an account and provisioning state, not a damaged chip. A SIM shipped but never activated, a disconnected line, a number moved onto a different SIM all land here. That is what “SIM not provisioned MM#2” is telling you: MM is mobility management, and the digit after the hash is the cause the network sent.

Cause #3 is the one that actually accuses the card. “Illegal MS” is sent when the network refuses service “either because an identity of the MS is not acceptable to the network or because the MS does not pass the authentication check, i.e. the SRES received from the MS is different from that generated by the network”. In plain terms, the card answered the cryptographic challenge with the wrong number: a genuinely faulty, tampered-with, or administratively blocked SIM.

Cause #6 does not concern the SIM at all. “Illegal ME” is sent “if the ME used is not acceptable to the network, e.g. blacklisted”. ME means mobile equipment — the handset. A phone reported lost or stolen is refused by its IMEI whichever SIM is in it. On this branch, a new SIM changes nothing.

Three more stop you testing a card that is fine. Cause #11 is “PLMN not allowed” and #13 “Roaming not allowed in this location area” — the SIM is healthy, but this network will not carry it here. Cause #17, “Network failure”, is sent when the network “cannot service an MS generated request because of PLMN failures”, entirely their side.

Carriers describe the same split. Verizon states plainly that “Your SIM card must be associated with an active line on your Verizon account to connect to the network”, and that “If your line is suspended, disconnected, or otherwise not allowed to connect to the network, this must be corrected”. A healthy chip on a deprovisioned line and a broken chip look identical from the couch, and they need different repairs — one is a phone call, the other a store visit.

Reading the message you have

The five-minute test, in order

Ordered by what is most likely and cheapest to rule out. The first two steps cost nothing and eliminate most of the tree.

1. Force a fresh registration. Airplane mode on, wait 30 seconds, off. The phone tears down and redoes the attach, which clears a stuck registration and otherwise reproduces the exact error instead of a stale one.
2. Read the message precisely, including the number. Write the whole string down. A trailing number is the reject cause, and it decides which of the three failures you have.
3. Ask whether the phone can see the card at all. Look for an ICCID (physical SIM) or EID (eSIM) on the About or SIM status screen in Settings. Menu names vary by phone maker and OS version, so search settings for “ICCID”. If a serial number is displayed, the chip and the reader are talking and the hardware branch is mostly closed.
4. Check the line on your account, over Wi-Fi. Sign in to your carrier’s app or site and look at the line’s status and balance. A suspended, disconnected or otherwise blocked line produces the same dead screen as a broken card. If the line is missing, or your number shows on a device you do not own, stop here and read the last section.
5. Physical SIM only: reseat and inspect. Power the phone off, take the tray out, check the gold contacts under a light for cracks, wear or corrosion, wipe them with a dry lint-free cloth, and put the card back squarely. Then, if you can, try the card in another unlocked phone. If it registers there, your card is alive and the fault is the reader or the phone. If a known-good SIM also fails in your phone, look at the account and provisioning causes that mimic a dead SIM.
6. If it says SOS only, the radio is finding a tower and being refused — a different question, with its own guide linked below.

If it is an eSIM, the standard advice is wrong

Every article that tells you to “try the SIM in another phone” assumes a card you can remove. An eSIM is not a card. The eUICC is soldered to the board and the profile on it was delivered over the air, so the usual first test is not available to you.

Run it in reverse. Put a different working SIM — a friend’s, a prepaid starter, an old line — into the same phone. If that line registers, the antenna, modem and reader are all fine, and the failure is your profile or your line.

The substitute people improvise is the harmful part: deleting the eSIM profile to “reset” it. That is not a reset. The profile is the only copy on the device, deletion is irreversible from your side, and restoring service needs the carrier to issue a fresh QR code or push a new profile — which you may not be able to receive, having no service to receive it with. Verizon says a deleted eSIM means it must generate a new profile for you to download again. Toggle the line off and on. Do not delete it.

If the phone was fine and then it wasn’t

A phone with normal service, in a place with normal coverage, that drops to nothing with no update, no travel and no bill trouble deserves one suspicion before any hardware theory. Verizon puts it bluntly: “In some cases, you might not know this has even happened until your phone no longer works.” That is a SIM swap — someone convinced your carrier to move your number to a SIM they control, and your calls and texts now land on their device.

The scale is not marginal. The FBI’s Internet Crime Complaint Center logged 320 SIM-swap complaints with roughly $12 million in losses from January 2018 through December 2020, then 1,611 complaints and more than $68 million in adjusted losses in 2021 alone. Once the swap lands, “the victim’s calls, texts, and other data are diverted to the criminal’s device”, which is how text-message password resets get intercepted; the FBI advises consumers to “Be aware of any changes in SMS-based connectivity”.

The FCC wrote protections into rule text in 2023. Adopted November 15, 2023 and published at 88 FR 85794 on December 8, 2023, effective January 8, 2024, the SIM-swap order adds 47 CFR 64.2010(h). Paragraphs (h)(2)–(6) and (h)(8) were delayed pending OMB review and still read “[Reserved]” in the codified section. As adopted, the parts read like a checklist of what to ask for: secure authentication before a SIM change is executed, reviewed “not less than annually”, with safeguards so employees taking inbound calls cannot reach your account records until you are authenticated (h)(1); “immediate notification to the customer” upon receiving a SIM change request and before it is carried out (h)(3); an account lock offered “at no cost”, which the provider “shall not fulfill a SIM change request until the customer deactivates” (h)(4); a free fraud-reporting process, prompt remediation, and documentation of fraudulent SIM changes “upon request” (h)(6).

Be careful how you use that at the counter, because the paragraph carries its own compliance clause. In July 2024 the Wireline Competition Bureau denied the industry’s request to waive the rules until March 2025, but waived compliance with the non-OMB rules until the reviewed ones take effect, creating “a single synchronized timeframe” tied to a Federal Register compliance-date notice. As of August 28, 2026 the codified text still reads: “Compliance with this paragraph (h) will not be required until this paragraph is removed or contains a compliance date.” So do not argue the citation — ask for the product, which carriers already ship voluntarily. Verizon’s SIM Protection is free and blocks “all transactions requiring a new SIM, including SIM swaps, device upgrades, and bring-your-own-device transactions”; it adds a 15-minute delay after you turn it off, and “our retail and customer service representatives are not able to turn SIM Protection off for you — it must be disabled through the My Verizon website or the My Verizon app”. That cuts both ways: a social engineer on the phone cannot lift your lock, and neither can a clerk processing your own legitimate replacement.

If a swap already happened, the sentence to use is: “I think my number was transferred to a SIM I do not control. Please treat this as SIM swap fraud, restore the line to my device, and send me written documentation of the fraudulent SIM change on my account.” Then change the passwords on every account that uses text codes, starting with email and banking.

What this page cannot settle

It cannot read your account, and that is where most of these cases resolve. It also cannot promise your phone will show you the number: manufacturers paraphrase reject causes, some phones display nothing but “No Service”, and a few show a cause the network sent minutes ago. When the message is generic, a failed card and a deprovisioned line are indistinguishable from outside, and the account check in step 4 is the only thing that separates them.

The cause definitions come from the 3GPP specification, which says what the network means when it sends a number, not what your carrier’s provisioning system did to earn it. The protections above are the rule as adopted, with compliance status as checked on the date at the top — carrier policy is what you meet at the counter, so ask for the feature by name.