Why do only certain apps show no internet connection on my iPhone 12?

JohnLarsen12 wrote:

Thanks once more for trying to help.

“Net only” is “phone net only” aka roaming.

VPN is installed, but since about a year not installed. Why would VPN cause this kind of problem on three app’s and the update app?

That doesn't make sense. "VPN is installed, but since about a year not installed?" Either there is a VPN profile on your iPhone or there isn't a VPN profile on your iPhone? And if there is a profile, VPN's often cause issues like you're seeing. They are just not needed, even if not actively used. The profile can cause an issue. If you do have a VPN on your phone, remove it completely. Don't just turn it off. Remove it. Settings > General > VPN & Device Management. Once the profile is removed, see if the issue with the apps continue. I'm betting the issues will be gone.

JohnLarsen12 wrote:

Thanks for your reply, but as I wrote: ‘If I disconnect wifi and BT, running the phone net only (same as mine)only, the same issue exist.

Meaning that also when being connected to the wifi, that works fine with the other units, there is no access using the mentioned app’s and trying to update iOS. Wifi also confirmed OK when using other app’s, including Chrome and Safari browsers.

Is a VPN app installed here? If so, remove it, and test again

Remove the VPN, and test.

You can re-install it later.

VPNs inherently mess with network routing, and the need to perform personally-identified metadata collection of all your activities can override everything else, including basic function. Or the VPN can be buggy. Or both.

JohnLarsen12 wrote:

Sorry, VPN is installed but currently not activated.

We often use VPN when travelling abroad and has never previously seen this issue.

Will tomorrow uninstall and see what happen.

Is you VPN advise linked to any specific VPN, or is it general?

Just about ALL VPN's cause issues with connectivity on iPhone. Unless you are required to use one for work or school (which should be provided by the employer or school) to access their servers, VPNs are just unnecessary and cause issues like you're seeing. One thing you should know about VPN is they DON'T provide the security you think they do. They are tracking everything you do on your phone, and most VPNs sell your data to anyone willing to pay for it. You honestly couldn't pay me to put a VPN on my phone.

Read this too --> VPN: What you need to know - Apple Community

VPN can do this and should never be installed.

What happens on wifi?

JohnLarsen12 wrote:

Thanks for your reply, but as I wrote: ‘If I disconnect wifi and BT, running the phone net only (same as mine)only, the same issue exist.

Meaning that also when being connected to the wifi, that works fine with the other units, there is no access using the mentioned app’s and trying to update iOS. Wifi also confirmed OK when using other app’s, including Chrome and Safari browsers.

I have no idea what "net only" means if wifi is off.

As MrHoffman said, you didn't reply to my point about VPN, which broad term includes many adblockers and so called security apps.

If you have some units that work and one unit that doesnt, what is different, and that usually means software in the absence of double modem failure.

JohnLarsen12 wrote:

There are situations where VPN is the only possible solution.

As I stated in my 1st input, there is no difference between phone net(roaming) and wifi(which is known good because of being used with several other devices).

VPN is the last resort for thieves or dissidents.

phone net(roaming) is a term you made up, sorry. Maybe you meant On Cellular connection?