No SSL on iPhone mobile data but WiFi is fine

[ftljouster]

iPhone 8 (iOS 16) on a SIM-only contract, but the issue has persisted across a couple of hand-me-down phone updates and iOS versions. Most apps and browsing do not work on mobile data, only on WiFi. Chrome gives ERR_SSL_PROTOCOL_ERR and Safari the message about being unable to establish a secure connection. Can send text only messages, but no images. WiFi is fine. O2 have tried a new SIM, and say there are no blocks on the account. APN settings have been reset, the time on the phone is correct, no VPN profiles installed. Phone has been factory reset and restored from backup, and was soft rebooted and had its network settings reset before that. It's as if O2's mobile network is preventing connections to remote port 443, or there is something on the phone doing so.

I'm baffled - what am I missing? 

[pgn]

The standard responses in here have probably all been tried, @ftljouster - Guide: How can I sort out my network issues? 

Might be worth taking your phone into an Apple store and get it checked out at this point, if there's one nearby.

[ftljouster]

Thanks. Swapped the SIM with another iPhone and the issue follows the SIM. So it's not the phones, and since the SIM has also been replaced it's nothing physical to do with the SIM - must be something at the account end.

[pgn]

Time for a call to 202, around 8am in the morning, then - good detective work, @ftljouster!

[jonsie]

Change the APN to mobile.o2.co.uk to see if that fixes data

If it does then you need O2 to enable idata on the account

Other than that perhaps @O2Sarah- can take a look at your account online tomorrow

[O2Sarah-]

Good Morning @jonsie , Thanks for the tag 

@ftljouster I will Private message you so I can check your account 

[ftljouster]

No joy with 202. Just kept repeating that there was a problem with the local mast. This is with the phone able to connect to a website via mobile data on port 80 just fine and then fail at the TLS handshake on port 443. And the phone right next to it, on the same mobile network, being able to connect OK to both.

@O2Sarah- the owner of the account @kepler_girl  now has an account on here so you can DM her directly.

This is how it fails:

Trying 104.18.39.194:443...
Connected to www.ucl.ac.uk (104.18.39.194) port 443 (#0)
ALPN: offers h2
ALPN: offers http/1.1
Cipher selection: ALL
CAfile:/private/var/containers/Bundle/Application/
1AF1F138-193F-41B7-97E4-4CB05DA6D961/iCurlHTTP.app/
cacert.pem
CApath: none
TLSv1.3 (OUT), TLS handshake, Client hello (1):
OpenSSL SSL_connect: Connection reset by peer in
connection to www.ucl.ac.uk:443
Closing connection 0
TRANSFER INTERRUPTED ERROR [35]
Possible TLSv1 Failure by Server

Works on :80 for both wifi and mobile. Works on :443 for wifi.

[ftljouster]

@O2Ellie are you able to help with this technical issue (or even just throw it in the direction of a network specialist)?

Problem occurs anywhere (being unable to access secured websites) so it's not related to local outages. Problem follows the SIM if the SIM is swapped between phones, so it's not phone software (and WiFI is also fine). SIM has been replaced by an O2 shop, so it's not the physical SIM. The problems have been ongoing for a LONG time (can't access certain websites, can't send images in iMessage, certain apps don't work on mobile but some do). It's just that I recently saw SSL mentioned in a Chrome error message and thought to do some digging at network and port level.

From what I've been able to divine, SSL connections get dropped after initial connection success, but only via mobile data. Could it be that the number on the account was previously used for spamming or DoS attacks and there is some firewall block or filtering somewhere on the O2 network?

[ftljouster]

Still not fixed. Still unable to get any useful progress via phone or in store, and it turns out that the guy in store locked us into updated contracts without making that clear which means we can't just switch that phone to a different network. Also now getting messages from people who have found this thread and are asking if I know how to fix it, so posting to make it clear I've not managed to get it fixed myself.

[Dave-H]

@ftljouster I am new to O2 and I also have (had) the ERR_SSL_PROTOCOL_ERR problem.

I found a fix that works for me. 

Under the My O2 menu I went into More and completed the age verification to prove I'm 18+. 15 minutes after doing this the SSL errors are gone.