Unlocked iphone not working on other carriers?

This is very helpful and seems consistent with the earlier evidence from your postings. The phone is not activated on the Sprint network and the most likely reason is the fact a used sim was tried.

Here is what you should do at this stage.

If you are near an Apple Store simply request a Sprint sim--ask nicely😉. It must be done in person and not over the phone. The sims are free at the Apple Store. There are the same for all Sprint carriers. Usually, the one provided is SIMGLW436C.

A Sprint store will provide one to somebody opening an account in person or sims can be purchased online from many places.

At that stage, the next thing to determine is whether the MEID of the phone is already associated with a line on a Sprint account. Sprint can advise on that but from what you have posted that seems very unlikely.

If it is, then you need to reach advanced technical support at Sprint and explain there is a need to do a sim switch on the line and provide the ICCID of the new sim. You cannot do this yourself (unless you are very familiar with the way Sprint manages this matter and have the necessary ESN and ICCIDs to do the job).

If it is not, then you need simply to contact Sprint with the MEID and ICCID of the new sim and everything should work properly. Both the MEID and ICCID must be activated at the same time.

At this stage, there is absolutely no reason to believe Apple has anything to do with the matter or could help in any way. This, at this point, appears to be solely a process issue in which an iPhone is involved rather than an iPhone issue as such.

Only if both of the above approaches fail, is there a need to look further.

Sprint can certainly swap the sim on the backend provided it is not linked to another active MEID. Finding someone in Sprint to actually do that may require patience.

There is absolutely no harm in doing the DFU and it would be useful in case the issue is not resolved by Sprint. In that way user-modifiable software issues can be excluded entirely.

There is a slight chance that the problem is the sim card reader itself but one needs to go through the process of elimination to get to that point because the fact that an AT&T sim is not being read does not definitively prove the reader is defective.

It would be useful to cover all the bases before approaching Apple as otherwise, you will simply be redirected to Sprint and told it is a carrier rather than a device issue.

Sprint is unusual in that the sim ICCID and IMEI are "married" and must be activated and deactivated together.

Is your friend using Sprint itself or a Sprint MVNO?

Has the phone ever been used another carrier or ever replaced under warranty by Apple?

Did your friend activate a new Sprint sim?

There are three models that work: SIMGLW436C, SIMOLW416C and SIMOLW506C.

The Apple tips should not be needed to switch a Verizon iPhone to Sprint.

How to unlock your iPhone for use with a different carrier - Apple Support

One needs to be very precise when it comes to Sprint.

Activation in the Sprint world is a very different concept from how the term is used here on this forum.

Moving a Verizon phone like the one you mention to Sprint almost never causes a problem and when it does it is because some critical step has been omitted. When that happens the only way to fix the problem is to systematically eliminate possible causes.

A good way to start is to run the IMEI on Tello and see if it is clear for immediate activation. If not, then run it on Ting and see if will activate on the GSM side.

Depending on what the exact messages are in both cases the next steps in resolving the matter are well established.

Same here,I bought Iphone 6s from my native Country and used there for two months then i shifted to India and in 5th day...**** No Service.

I sent the phone back to my country through a friend,there all was well,he brought back to me and network was Ok,but after 5 day ‘No Service’.

Here in India IPhone Authorised centres don’t have any Idea in this regard.please let me know too if u find any solution.

****@ yahoo.com
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That is great news!.

Congratulations on getting it resolved--your patience and effort paid off.🙂