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I have moved my SIM only contract from VOXI to Sky Mobile today. I was with VOXI from July 2019 but carried on using my Vodafone SIM as they're obviously the same network. Before VOXI I had a monthly SIM only contract with Vodafone for about 3 years. My unlocked iPhone 6s was purchased from John Lewis and was nothing to do with Vodafone.
After installing the Sky SIM today everything seemed to be fine. I installed the Sky configuration file and all seemed well. However, when I checked in my Mobile Data settings, I noticed that my Mobile Data APN was still showing as pp.vodafone.uk. I called Sky and they suggested that I just overtype the APN to be mobile.sky. I did this, but when I then tried to access the internet using 4G I was unable to do so and received the error message that there was no mobile data network available. When I changed the APN back to Vodafone I was able to connect I imagine because I still have a few weeks left on my final VOXI payment.
The Sky engineers suggested that my phone is probably locked in some way to Vodafone even though the phone was not purchased from them? Sky can't do anything at their end and suggest that I approach Vodafone for an unlock code. The weird thing is that the phone is using Sky 4G for phone calls and is working? Can anyone help? Would Vodafone really have locked my phone even though it wasn't purchased from them? Any help would be appreciated.
Even if the phone came from Vodafone, the 6S would be already unlocked. You also mention you are able to use the Sky SIM in the phone without any problems and it's only APN settings where you are having issues.
I would suggest you follow this link from Apple: View and edit your Access Point Name (APN) on your iPhone and iPad . You will probably find the APN settings are defaulting to Vodafone, if you follow the guide, you will be able to reset and delete the Vodafone profile. Also, try completing the process by synchronising your to itunes account, this will download the correct carrier settings.
Thank you AnnS. As it turns out, it was user error on my part. Although I thought I had installed the new config file properly, when I reset all the original settings and then went back to install the config file again it asked me this time to remove the Vodafone PAYG APN first. Once I did that, the Sky Mobile APN installed properly and life is good.
Thank you so much though for responding so promptly and I'm sorry that I wasted your time!