SIM recognizes, but no network

[badslipper]

Hi all,

I have a strange problem with a OnePlus 5T. I used it myself for a while without any issues in combination with dual SIM on the Dutch Odido and Simyo networks. Everything worked perfectly.

I have now bought an FP6 myself and want to give the 5T to my daughter. So I reset it to set everything up again. However, her Simyo SIM is recognized, connects briefly (4G), and then loses connection after about 5 seconds. The settings show that no network is available. Her SIM does work in other phones (iPhone and my new FP6, also e/os).

If I then put my Odido SIM into the 5T, it works just fine.

I have also tried both SIM slots, but that makes no difference.

Does anyone know how I can solve this?

Regain your privacy! Adopt /e/OS the unGoogled mobile OS and online services

[aibd]

@badslipper

SIM is recognized, connects briefly

One might think this was an APN setting thing apn but a few seconds only of connection is odd. APN changed a bit for 2026 but in this thread we seemed to talk through all the usual suspects including a link to 2026 troubleshooting. You mention 4G, seems probably APN is now quite highly dependent on IMS registration.

United States SIM unrecognized (/e/OS 3.7.2 on FP3)

I am currently in the United States: when I slotted the physical microSIM card I have here (carrier: Tello, a T-mobile MVNO) into my FairPhone it works for a while (~10 minutes), then the phone reports that there is no SIM card inserted. If I turn the phone off and on again, it still reports that there is no SIM, but if I take the battery out, physically remove the SIM and then slot it back in, when I turn the phone on it gives me another ~10 minutes of normal functioning, before cycling back to…

[badslipper]

Hi, thanx for you reply.

The strange thing is that the SIM card is recognized. However, I cannot connect to the provider’s network (yes, very briefly).

I manually configured the provider Simyo’s AP settings, but unfortunately, that didn’t work either.

[aibd]

Did you read it as a wakthrough of things to do?

@Taurus

Have you tried checking the IMS registration status by dialing *#*#4636#*#*?

Then a few posts further on is the 2026 troubleshooring tips when APN doesn’t work first time.

[badslipper]

Yes, I have read all the steps, but I don’t understand everything. The SIM card is actually recognized in my phone.

I’ve made some progress now. I set the preferred network mode to LTE and set the access point and network type to LTE, EDGE, GPRS. The internet is working now, but I still can’t make or receive calls.

Under IMS it says the following:

Phonenumber: +31******* {CARRIER:, UICC: +31*******, IMS:}

For comparison with my working FP6:

Phonenumer: +31******* {CARRIER:, UICC:, IMS: +31*******}

I don’t know very much about UICC and IMS, but can I adjust that manually somewhere? It looks Luke UICC is nog used and IMS should list my phonenumber.

[aibd]

IMSI is the numerical code given on IMS registration https://imeicheck.net/blog/what-is-imsi-number-how-to-check-and-lookup-imsi.

Some more clues to the need for IMS in that blog post.

Hopefully this is the IMS of the new card and not the ghost of the SIM card before Factory reset (though I doubt this is likely).

@badslipper

I still can’t make or receive calls.

Good to include a restart after changes so that those transfer to SIM.

If you are on the carrier network if you are getting mobile data; try @badslipper

@aibd

Reset to Default:
Navigate to APN settings, tap on top right 3 dot menu, and select Reset to default.

[badslipper]

After rebooting I am stil not on the carrier network. Only internet works, I van stille not make any calls. Still no IMS.

[aibd]

If IMS registration is missing and nothing else works I suggest to call the carrier.

Perhaps ask if “Network reset” is available and is expected to fix IMS. The alternative would be to ask for “APN reset” but the IMS registration is probably the most important to have corrected.

This will hopefully fix the issue as happened in the final post of the linked thread.