Hello, dear /e/ community,
I recently had /e/ applied to my Samsung A3 (2016). The system runs great. All necessary apps (e.g. DB Navigator, TAN apps) run without any problems. Thanks to the makers of /e/ !
Unfortunately, a BUT: the inserted SIM card is not recognized. It works on another smartphone. A card from another provider is also not recognized. So I guess it must be the A3. Does anyone have any advice on how I can solve the problem?
Mfg
peteos
Please can I clarify if the SIM was installed when you ran the Fist start wizard, and do you see this at that time or subsequently?
I have the same phone, never saw this issue but I always have the SIM at first start.
But also, worth checking if you go to Settings > Network and internet > Mobile network do you see your carrier mentioned by name? (This would double check that the card is really not detected.) I do often get the situation where I have to ask my carrier to send APN (Access point names) found under > Advanced from the above point.
Hello aibd,
thanks for the reply. I did not install the os myself. But I asked the installation service and I am waiting for an answer.
When I cam across these symptoms, it was because there was a problem with the build (which was an unofficial build, made by me). Which build are you using?
I do not know, what is the right information.
/e/ OS Version: 1.1-q-20220629200240-dev-a3xelte
Build-Nr.: e_a3xelte-userdebug 10 QQ3A.200805.001 eng.root 20220629.162737 dev-keys, dev-release
Does it help?
Great, even just the first entry shows that you have an /e/ version 1.1 official Android 10 (q) {date 20220629 | build identifier 200240 | your device a3xelte – in there too}. I confirm that I have run that without SIM issue.
I expect Settings > System updates > Refresh may offer you an update to 1.2 which runs slightly more nicely for me.
Thanks for the tip. I have made the update (on 1.2). But it did not solve the problem.
@aibd
During the first installation auf /e/ a SIM-test was included and it worked. I’ve got the phone back without that SIM and put my own into it.
In this case the other question I already asked was this:
There is a trick you might do now; a Force stop. Press Vol down + Bixby + Power for > 7 seconds and a reboot will happen. Test for SIM again.
If you get to “Reset to default” with no luck, it is time to contact the carrier, explain your predicament and ask them to send you the settings. They may be under the impression that this should have happened automagically (perhaps in /e/ the magic is different).
(More ideas perhaps from a search using this link https://community.e.foundation/search?expanded=true&q=APN%20 )
Thanks for the tips. I have read through the links. But they do not solve my problem.
I was referring to the Home/Bixby button, bottom centre of the screen! 
Indeed you will have done a reboot with the update. We do not know if a Force stop will help, but it is different and more powerful than reboot in some circumstances. (Sometimes this type of reboot is called a Soft reset.)
I do think it will be quite significant to know if your carrier or the installer’s “temporary carrier” is mentioned in the location I offered twice.
Sorry if I didn’t answer it. If I did understood the question correctly:
So maybe this is not going to be resolved by APN. After all your research are you still feeling that the SIM card is simply not recognised at all? No “Emergency calls only”?
If Soft reset does not work you may find you have to consider doing a Factory reset with SIM in place. This will remove your apps and data, but you will retain the existing /e/ 1.2 version.
So it is! The SIM is absolutly not recognised. No Emergency calls possible.
OK, than a factory reset. It is my “/e/ test smartphone”, therefore it is not a problem concerning apps and data.
But I am a beginner at /e/. So please send me a link where I can find tips for a factory reset (for beginners).
I guess, now it starts a hard way for mie to learn /e/. 
Not so hard!
Settings > System > Reset options > Erase all data.
You should have a battery charge level > 60%.
But you did try Soft reset first?
Hello aibd,
a new soft reset did not bring anything. So I made a system reset as recommended. Bingo! The SIM is now recognized at /e/ and works without problems. Thanks a lot for your help.
I knew it, /e/ is a fantastic operating system, which I will gladly recommend and soon put on my “daily phone”.
Best regards
Peter
@aidb
I have found the cause. When screenlock is set to none, the SIM will not be detected. If I change to wipe, the sim is detected after a soft reset and works without problems.
It sounds like a bug to me. This problem does not exist under G-Android.
I could not reproduce that!
I changed Settings > Security > Screen lock to None.
I connected a phone call.
I Soft reset; connected a phone call; reboot; connected a phone call; checked each time that Screen lock remained off.
I cannot help wondering if there are certain SIM cards which do not work well with /e/. Compare this post: Location doesn't work - #10 by yz3en. (Pure speculation; what if … a carrier required a call to Google under certain circumstances?)
You might care to share the carrier you are using.