Wired
While using iPhone / iPad, one day suddenly a “SIM error” was displayed and communication on the cellular line became impossible. Even if I restarted the main unit or updated the carrier settings, it did not improve, and finally I replaced the SIM card with a new one and solved it.
“SIM error” suddenly appears
While using the 11-inch iPad Pro with the NTT DoCoMo SIM card inserted, I noticed that the carrier name was not displayed, and the antenna icon and antenna pictogram indicating the signal strength were not displayed.
When I restarted there, I found that a “SIM error” was displayed on the screen and communication was not possible.
Until “SIM error” is displayed
Until the “SIM error” was displayed, communication was possible without any problems. The SIM card is from NTT DoCoMo’s “Xi Data Plan Flat Ninen” contract, which I have been using for 9 years and 4 months.
The usage environment did not change before and after the error was displayed, such as updating the iOS / iPadOS, getting the device wet, inserting and removing the SIM card, and so on.
Follow the Apple Support information
First, I checked the page titled “If the SIM card is not inserted” or “Invalid SIM” is displayed on the iPhone or iPad of Apple Support, and tried to solve the problem.
Have you signed up for a carrier plan and is the plan valid?
The plan I am using is the one I am using, and there is no delay in payment. In addition, it was confirmed that the mobile phone with the FOMA line linked with “Xi Data Plan Flat Ninen” can be used without any problem.
Update to the latest iOS / iPad OS and restart
The information on the Apple Support page recommends updating to the latest iOS / iPad OS as the second check, and rebooting as the third.
I’ve already updated to the latest iPad OS, so I did a third reboot (I’ve done multiple reboots so far). I also tried turning airplane mode on and off.
However, the “SIM error” was not resolved.
Check for carrier settings updates
Fourth, it says to check if there is an update of the carrier setting, so when I checked it, the message “Do you want to update the carrier setting?” Was displayed.
When this message was displayed, I thought that the reason why I could not update the carrier settings was that communication was not possible, so I updated it immediately.
However, it did not become communicable, and even after restarting, the “SIM error” was still displayed.
Remove and reinsert the SIM card
Fifth, it says “Remove the SIM card from the SIM card tray and insert it again”, so I tried it, but the “SIM error” was not resolved.
Try inserting another SIM card
Sixth, you are instructed to “try inserting another SIM card. If not, have your carrier test it with another SIM card.”
When I inserted the IIJmio SIM card used in the iPhone 12 Pro, it was confirmed that the carrier name and antenna pictogram were displayed on the 11-inch iPad Pro.
Try inserting the SIM card in question into another device
When I put a SIM card that displays “SIM error” into the iPhone 12 Pro, it was confirmed that the same error occurred here as well.
I thought this wasn’t the problem with the device, but the problem with the SIM card.
When replacing the SIM card, the profile is not installed because the purpose is not to switch the card to be used.
However, since the antenna pictogram was displayed, I thought that communication would be possible if only the profile was installed.
Call your carrier’s retailer
If there is no possibility of a “SIM error” due to a device failure, the Apple Support page states that “SIM card may need to be replaced”, so the NTT DoCoMo store (My I contacted my shop (registered with docomo) and reported the symptoms.
The person in charge replied, “The SIM card may be out of order, so please come to the store.”
Visit a carrier’s retailer and insert a test SIM card
At the NTT DoCoMo store, after confirming the symptoms, I was instructed to insert a SIM card for testing, and I tried inserting it into the 11-inch iPad Pro.
“Mobile data communication” in the “Settings” app used to display “Add mobile communication plan”, but it has changed to “Mobile communication plan: docomo SIM card”.
I was able to confirm that the carrier name and antenna pictogram were displayed on the home screen of the 11-inch iPad Pro.
Diagnosis of the SIM card in question
As a result of the store diagnosing the SIM card with “SIM error”, it was confirmed that the same problem appeared, and it was confirmed that the SIM card was out of order.
There was no physical damage to the SIM card terminals, and on the surface I could not tell the difference from a normal SIM card.
SIM card exchange procedure
The SIM card exchange procedure was free. It seems that you will need the SIM card PIN unlock code (PUK) and network PIN for replacement.
I gave the necessary information and proceeded with the procedure.
The person in charge took out a new SIM card in front of me, wrote the data, put it in the 11-inch iPad Pro and tested it. It was confirmed that communication was possible without any problems, and the SIM card replacement procedure was completed.
Summary
I got a “SIM error”, so I followed the Apple Support page to fix the problem.
Eventually, it turned out that it was not a malfunction of the device such as iPhone or iPad, but a malfunction of the SIM card itself, so we had you replace it with a new SIM card after about 30 minutes of diagnosis and procedure at the NTT DoCoMo dealer. The problem has been resolved.
Even if you can’t see any physical damage to the surface of the SIM card, it seems that it may be out of order.
Points to check when “SIM error” is displayed
Source: Apple Support, NTT DoCoMo Customer Support, SoftBank Support
(FT729)
Source: iPhone Mania