Cellular network operator O2 on Friday said its data networks had been restored after millions of smartphones across the UK and Japan were taken offline yesterday (via BBC).

A statement on its website said the 4G network was finally working again, after having been affected from about 05:30 GMT on Thursday.

o2 ericsson
Earlier, mobile network equipment supplier Ericsson said that an expired certificate was the reason behind the outage, which also created problems in several other countries. Ericsson UK boss Marielle Lindgren said the "faulty software" that had caused the issues was being decommissioned.

Both O2 and Ericsson issued a joint apology to millions of customers hit by the disruption. "I want to let our customers know how sorry I am for the impact our network data issue has had on them, and reassure them that our teams, together with Ericsson, are doing everything we can," said O2 boss Mark Evans. "We fully appreciate it's been a poor experience and we are really sorry."

O2 is owned by Spain's Telefonica and has the UK's second-largest mobile network after British Telecom subsidiary EE.

The company said voice calls were not affected by the problem, but some O2 customers said they could not make calls or send texts, despite having cellular reception.

The outage also had knock-on effects for other services that use the O2 network, such as Transport for London's electronic timetable service at bus stops, which stopped working for most of Thursday.

Top Rated Comments

fullfast Avatar
92 months ago
Vodafone is the Verizon of the UK. I’ve tested all the networks and for me it was the best by far. Glad O2 is good for you
30 million total impacted by it and all because some dope forgot to renew a certificate so it expired.....that is just pi$$ poor management

Luckily for me I am on both Vodafone and o2 so minimal impact but it does just show how reliant we are now on being able to access internet services.......rewind 15 years....you were lucky if you could receive texts let alone look at what some dog or cat is doing on insta :)
Score: 4 Votes (Like | Disagree)
BMcCoy Avatar
92 months ago
As frustrating as yesterday’s outage was, I still think we do quite well in the U.K. for our cellular deals, whether calls or data. We pay about a quarter of what it costs in the US.
Score: 4 Votes (Like | Disagree)
jimthing Avatar
92 months ago
I moved from O2 to EE when I got a Series 4 on launch. Very happy. My wife and kids are on O2 still, and I didn't hear from them all day yesterday. Who do I send the thank you letter to?
Here's the address:

(FAO) 'Men escaping constant annoying trivial family calls' dept
Santa Claus
iCloud
Earth
Space
Universe
Score: 3 Votes (Like | Disagree)
NoFace1006 Avatar
92 months ago
Vodafone is much better.
You're joking aren't you?! Although I should say that everyone has different experiences and it depends where you live, etc. Had several family members on Vodafone over the years and it's always been terrible for data, particularly data reception more so than the speed. In the end everyone has moved over to other networks, I've been with 3 for 18 months after switching from O2's network, couldn't be happier. Went to the top of Scotland to visit family, a no reception area for most networks in places, I was the only family member with signal and data access.
Score: 3 Votes (Like | Disagree)
coumerelli Avatar
92 months ago
They apologize by you still get billed for the time it was out I bet...
Yeah. All 0.17£/€/¥. lol
Score: 2 Votes (Like | Disagree)
roar08 Avatar
92 months ago
It'll be interesting to find out of this tantalizing Mac rumor turns out to be true.
Score: 2 Votes (Like | Disagree)

Popular Stories

iOS 26

iOS 26.2 Coming Soon With These 8 New Features on Your iPhone

Thursday December 11, 2025 8:49 am PST by
Apple seeded the second iOS 26.2 Release Candidate to developers earlier this week, meaning the update will be released to the general public very soon. Apple confirmed iOS 26.2 would be released in December, but it did not provide a specific date. We expect the update to be released by early next week. iOS 26.2 includes a handful of new features and changes on the iPhone, such as a new...
Google maps feaure

Google Maps Quietly Added This Long-Overdue Feature for Drivers

Wednesday December 10, 2025 2:52 am PST by
Google Maps on iOS quietly gained a new feature recently that automatically recognizes where you've parked your vehicle and saves the location for you. Announced on LinkedIn by Rio Akasaka, Google Maps' senior product manager, the new feature auto-detects your parked location even if you don't use the parking pin function, saves it for up to 48 hours, and then automatically removes it once...
Foldable iPhone 2023 Feature 1

Apple to Make More Foldable iPhones Than Expected [Updated]

Tuesday December 9, 2025 9:59 am PST by
Apple has ordered 22 million OLED panels from Samsung Display for the first foldable iPhone, signaling a significantly larger production target than the display industry had previously anticipated, ET News reports. In the now-seemingly deleted report, ET News claimed that Samsung plans to mass-produce 11 million inward-folding OLED displays for Apple next year, as well as 11 million...
AirPods Pro Firmware Feature

Apple Releases New Firmware for AirPods Pro 2 and AirPods Pro 3

Thursday December 11, 2025 11:28 am PST by
Apple today released new firmware designed for the AirPods Pro 3 and the prior-generation AirPods Pro 2. The AirPods Pro 3 firmware is 8B30, up from 8B25, while the AirPods Pro 2 firmware is 8B28, up from 8B21. There's no word on what's include in the updated firmware, but the AirPods Pro 2 and AirPods Pro 3 are getting expanded support for Live Translation in the European Union in iOS...
iOS 26

15 New Things Your iPhone Can Do in iOS 26.2

Friday December 5, 2025 9:40 am PST by
Apple is about to release iOS 26.2, the second major point update for iPhones since iOS 26 was rolled out in September, and there are at least 15 notable changes and improvements worth checking out. We've rounded them up below. Apple is expected to roll out iOS 26.2 to compatible devices sometime between December 8 and December 16. When the update drops, you can check Apple's servers for the ...
AirTag 2 Mock Feature

Apple AirTag 2: Four New Features Found in iOS 26 Code

Thursday December 11, 2025 10:31 am PST by
The AirTag 2 will include a handful of new features that will improve tracking capabilities, according to a new report from Macworld. The site says that it was able to access an internal build of iOS 26, which includes references to multiple unreleased products. Here's what's supposedly coming: An improved pairing process, though no details were provided. AirTag pairing is already...
iOS 26

Apple Seeds Second iOS 26.2 Release Candidate to Developers and Public Beta Testers

Monday December 8, 2025 10:18 am PST by
Apple today seeded the second release candidate version of iOS 26.2 to developers and public beta testers, with the software coming one week after Apple seeded the first RC. The release candidate represents the final version iOS 26.2 that will be provided to the public if no further bugs are found. Registered developers and public beta testers can download the betas from the Settings app on...
iPhone 14 Pro Dynamic Island

iPhone 18 Pro Leak Adds New Evidence for Under-Display Face ID

Monday December 8, 2025 4:54 am PST by
Apple is actively testing under-screen Face ID for next year's iPhone 18 Pro models using a special "spliced micro-transparent glass" window built into the display, claims a Chinese leaker. According to "Smart Pikachu," a Weibo account that has previously shared accurate supply-chain details on Chinese Android hardware, Apple is testing the special glass as a way to let the TrueDepth...
Home Hub Command Center with Dome Base Siri Finder Feature

iOS 26 Code Leak Reveals Apple Smart Home Hub Details

Thursday December 11, 2025 4:02 pm PST by
Apple is working on a smart home hub that will rely heavily on the more capable version of Siri that's coming next year. We've heard quite a bit about the hub over the last two years, but a recent iOS 26 code leak provides additional insight into what we can expect and confirms rumored features. Macworld claims to have access to an internal version of iOS 26 that references several upcoming...
studio display purple

Apple Studio Display 2 Code Hints at 120Hz ProMotion, HDR, A19 Chip

Thursday December 11, 2025 4:19 am PST by
Apple's next-generation Studio Display is expected to arrive early next year, and a new report allegedly provides a couple more details on the external monitor's capabilities. According to internal Apple code seen by Macworld, the new external display will feature a variable refresh rate capable of up to 120Hz – aka ProMotion – as well as support for HDR content. The current Studio...