Hello there :)
[TLDR
After playing around with MPTCP in the iOS developer menu system apps are unable to connect to the internet. The problem comes back every morning now and is mitigated by a restart.]
I am playing around with Multipath TCP in my company and I knew there was a setting in the iOS developer menu that allowed modifying my iPhones behaviour. So, I plugged my iPhone 11 Pro with iOS 13.5.1 into my Mac with Xcode and used the developer menu on the phone to play around with the settings of Multipath TCP there.
I noticed that despite me flipping the switch to turn this mode on and chosing one of the options there, when I went back into the menu above the switch was flipped back off. Despite that, suddenly my phone seemed to not be able to connect to the internet anymore.
After a restart the problem was gone, so I plugged the cable back into the phone, enabled the developer menu again and tried again with no different result.
Another restart later I gave up, but noticed after a few hours, that in the middle of me using the phone suddenly my internet connection seemed to be gone. I was connected to the Wifi, other devices on the network were working fine but Safari and some Apps, that I tried were unable to connect to the internet. I restarted the phone again and the problem was gone - for a while.
Next morning I woke up, picked up the phone from the charger and again, Safari, Mail and many apps were unable to connect. Then I tested some Apps that I often use for network debugging like "HE Network Tools" or "a-Shell" and I was curious to see, that actually those apps were still able to send ICMP requests and resolve DNS querys. So maybe, despite Safari not being able to browse the web, other apps were still able to utilize the OS to connect to the network.
I tried to reset my network settings, hoping to resolve the issue, but even sacrificing my Wifi passwords by doing this did not help, the problem occured now the third day in a row in the morning.
Do you have any idea what could cause this and how I can fix it without deleting all my data? I fear, restoring my phone from a backup after a clean reinstall of iOS might also bring back a broken configuration that leads to this problem, so I'm not sure if it's worth the trouble of having to set up Apple Pay, all the banking two-factor apps and other things that don't restore with a backup.
Thanks for your ideas,
Thomas
[TLDR
After playing around with MPTCP in the iOS developer menu system apps are unable to connect to the internet. The problem comes back every morning now and is mitigated by a restart.]
I am playing around with Multipath TCP in my company and I knew there was a setting in the iOS developer menu that allowed modifying my iPhones behaviour. So, I plugged my iPhone 11 Pro with iOS 13.5.1 into my Mac with Xcode and used the developer menu on the phone to play around with the settings of Multipath TCP there.
I noticed that despite me flipping the switch to turn this mode on and chosing one of the options there, when I went back into the menu above the switch was flipped back off. Despite that, suddenly my phone seemed to not be able to connect to the internet anymore.
After a restart the problem was gone, so I plugged the cable back into the phone, enabled the developer menu again and tried again with no different result.
Another restart later I gave up, but noticed after a few hours, that in the middle of me using the phone suddenly my internet connection seemed to be gone. I was connected to the Wifi, other devices on the network were working fine but Safari and some Apps, that I tried were unable to connect to the internet. I restarted the phone again and the problem was gone - for a while.
Next morning I woke up, picked up the phone from the charger and again, Safari, Mail and many apps were unable to connect. Then I tested some Apps that I often use for network debugging like "HE Network Tools" or "a-Shell" and I was curious to see, that actually those apps were still able to send ICMP requests and resolve DNS querys. So maybe, despite Safari not being able to browse the web, other apps were still able to utilize the OS to connect to the network.
I tried to reset my network settings, hoping to resolve the issue, but even sacrificing my Wifi passwords by doing this did not help, the problem occured now the third day in a row in the morning.
Do you have any idea what could cause this and how I can fix it without deleting all my data? I fear, restoring my phone from a backup after a clean reinstall of iOS might also bring back a broken configuration that leads to this problem, so I'm not sure if it's worth the trouble of having to set up Apple Pay, all the banking two-factor apps and other things that don't restore with a backup.
Thanks for your ideas,
Thomas
