ThreeUK is blocking Tutanota. While ThreeUK says the applied adult filter was standard for any email provider, other services are not blocked.

ISPs must not have the power to decide which online services users can or can not access.

In the United Kingdom, ThreeUK internet users are unable to access Tutanota mailboxes on mobile connections since the beginning of November. Even though we reached out to ThreeUK over one month ago, the issue is still not fixed. A possible reason could be a wrongly applied adult filter. Regardless of what is causing the issue, this shows why net neutrality is so important for internet users and online services alike.

Update 2023-02-10: More than two months after reaching out to ThreeUK, it looks like ThreeUK has now fixed the issue. Please keep us posted if you experience issues accessing Tutanota on ThreeUK mobile.

ThreeUK mobile users are unable to access Tutanota

Starting beginning of November, we have had constant complaints from ThreeUK mobile users who were unable to access their encrypted Tutanota mailbox.

First we contacted ThreeUK via chat on November 11th. Back then ThreeUK said that Tutanota would be behind an 18+ filter based on UK law and GDPR guidelines. Their support member suggested that each Tutanota user must contact ThreeUk individually.

However, this did not solve the issue as people are still unable to access Tutanota - while accessing other email services works without any issue.

Here is a transcript of the conversation that took place between us and the ThreeUK customer support on November 11th 2022:

Tutanota 2:24 PM I am a customer support team member at Tutanota. We are an encrypted email provider based in Germany. This week a number of our UK customers reported problems connecting to their accounts when using your network. One user reported that a service team member at Three told them our site is being blocked by an adult content filter, is this true? I can assure you that we are not hosting any adult content, but offer an email service like Gmail or Hotmail.

ThreeUK 2:26 PM Thanks for reporting this to us. Don't worry, we're always here to help our customers with best possible resolution. I understand your clients are facing issue with accessing this website. All you need to do is just ask them to get in touch with us and we will validate your accounts and help them to get the restrictions lifted.

Tutanota 2:29 PM The accounts do not belong to us.

ThreeUK 2:29 PM It hardly takes a minute to get this done for them, so all you need to do is just ask them to start a chat with us, I'll explain you how this works .

Tutanota 2:30 PM We are under the impression that our web service is being blocked by Three's network.

ThreeUK 2:30 PM At times for security reasons, at times the email domains as well need 18+ permissions.

Tutanota 2:30 PM The affected customers all use Three for their mobile data and cannot use that connection to access their accounts. Is this due to a privacy law in the UK? Are domains like also blocked by this filter?

ThreeUK 2:31 PM You just need to inform them that Three as a network has a permanent solution to this. Any email account that you generate needs a 18+ confirmation.

Tutanota 2:32 PM And this can be confirmed in their account profile with Three?

ThreeUK 2:32 PM Yes, that's absolutely correct. So whenever this happens all you need to do is ask them to contact us Three network customer support. And we're here to fix this for them

Tutanota 2:33 PM Ok, we will inform our users of this policy.

ThreeUK 2:33 PM Thank you for your time. All we need to do is validate the account with them and this will definitely be taken care. Thanks for understanding the policy. And rest assured, its my word once they contact us we will get this sorted for them.

Tutanota 2:34 PM Is this policy an internal policy or a law within the UK?

ThreeUK 2:35 PM Its as per UK law and GDPR guidelines for all the network providers that run business in UK. We need to do a age verification check to get customers access to all the websites that requires 18+ permissions

Tutanota 2:35 PM Ah ok, if possible would you have a link or reference number for this law? It would help us present this solution to our customers. If not, I understand.

ThreeUK 2:36 PM Thanks for understand, things became easier to deal today as you mentioned you're from customer services, it becomes easier to help and address things. You can them this link and they can chat with us directly. Thanks for your time, shall I consider this query and chat as resolved today?

No other email service blocked

Even though we explained our users in support that they should contect ThreeUK directly, they kept reporting the issue to us, saying that contacting ThreeUK would not help. Besides they also tested the claim of the ThreeUK support member that "Any email account that you generate needs a 18+ confirmation" - and it turned out to be false. Accessing Gmail, Yahoo or any other email service works flawlessly on ThreeUK mobile connections, only access to Tutanota is blocked.

Contact via Twitter

We then turned to Twitter, trying to reach out to ThreeUk there.

While ThreeUK at first seemed willing to fix the issue when we reached out to them via Twitter, the issue is still not solved and reports from users keep coming in.

We reached out to ThreeUK again, but did not get a reply from the support team at all.

The conversation went dead.

Being in Germany, we are not able to test the issue ourselves, but our users confirmed that Tutanota is still blocked on ThreeUK mobile connections.

As ThreeUK has not fixed the issue more than one month since we first raised the issue with them, we are reaching out publicly in the hope of getting the attention of the right people at ThreeUK.

A similar outage happened in January 2020 when AT&T blocked access to Tutanota.

Back then the issue was fixed within one day after public attention.

How to evade ThreeUK block

Users of ThreeUK mobile who can't access Tutanota may use a vpn or the Tor browser to evade this block and to access their secure Tutanota mailbox.

Call to action: Battle for the net

Such outages demonstrate how much power ISPs are having over our online experience, and it is shocking. If ISPs can block access to certain websites or services, they control the Internet. It would be naive to believe that ISPs will not use this power. Without net neutrality ISPs can - and will - ask for extra fees.

ISPs could impose 'taxes' on websites

A free Internet guarantees that all online services are being treated equally: Right now we can access any website at the same speed. We are free to make a choice between all online services on offer without any disadvantage.

Without net neutrality, this changes. When all power lies with the ISPs, they decide what we see, what sites we are able to access. They can destroy a start-up before it has even started, simply by blocking their site. They could take money from corporations like Google and Facebook to offer 'fast lanes' to their users while smaller companies, start-ups or NGOs can not afford to do so.

Scrapping net neutrality laws will allow ISPs to impose 'taxes' on websites that in the end the user will have to pay. Our online experience will become much more unequal and much more expensive.

Corporate censorship will change the internet

Without net neutrality ISPs could, for instance, offer a 'US bundle', which allows users to use certain US services like Google, Facebook and Twitter without any data limit. If - or when - ISPs start creating such bundles, this will harm competition immensely because using services not included in such a bundle would become more expensive to the end-user.

Internet Service Providers such as ThreeUK, AT&T or Comcast could include or exclude any service from their bundles without having to justify their decision. Thus, they can decide what services their customers use.

Why net neutrality matters

1. To keep the Internet free

Removing the current net neutrality protections would allow Internet Service Providers like Comcast and Verizon to block content, to slow video-streaming services from rivals, and to offer 'service bundles' of preferred partners.

Users would not be free to visit any site or use any service they would want to, but would be limited to what their ISP offers.

2. To guarantee free competition

Ultimately, the limits imposed by Internet Service Providers will make it much harder for start-ups to even get started. When users only get unlimited access to certain preferred websites and services, most of them will never even try a promising new start-up because of extra charges.

However, it is competition and great start-ups that fuel the innovation of the Internet. There's a reason why monopolistic companies like ISPs, cable companies and telcos rank at the bottom of customer satisfaction studies - being monopolies they do not pay much attention to what their customers want and need.

While huge companies such as Google, Netflix or Amazon can most likely afford to sponsor data, smaller companies or start-ups don't necessarily have the budget.

Universal access and fast connections are most important when it comes to online services. So even if you are providing the better service compared to what a huge corporation has on offer, the big competition can always outplay you by simply paying for faster connections and better accessibility for their users. In the end, monopolies will control the Internet and your data. This will not only harm innovation, but it will also make online services more expensive for consumers. Without a choice of services, monopolies can raise prices at their own discretion as users won't have the option of switching services anymore.

3. To guarantee free speech

Net neutrality is important to guarantee free speech and, thus, to protect democracy itself. If net neutrality is lost, there is no way of turning back: Big corporations will own the Internet, big corporations will decide what we see online, big corporations will dominate the public opinion, big corporations will dominate any future decision to be made in Politics.

The Internet right now is bringing people together and giving them the possibility to discuss their beliefs and opinions in a mostly free and open manner. It's possible to gather a lot of information online even in countries where the ruling class censors the media.

By now, the Internet has become the perfect place to organize public resistance when the ruling class tries to seize too much power. A free and open Internet helps people all around the world to access uncensored information.

4. To enable free access to information and education

Most countries invest heavily in free education: free schools, free libraries for children and students, and so on. Without net neutrality, we harm one of the biggest resource to gather free information: the Internet.

Limiting access to this great information resource will disproportionately impact low-income families and limit everybody's potential to learn in our digital age.

If websites have to pay for fast lanes, accessibility of educational and non-profit websites will suffer as they will not have the funds, or prefer to spend their funds elsewhere instead of throwing it as ISPs.


The Internet as a free and open market place is great for information, innovation and competition. That's why the Internet needs to be treated like a utility, just like electricity or water. In our modern digital age, access to the Internet - and to all its content at the fastest possible speed - has become a basic necessity to all of us.

Handing such an important tool entirely over to companies that care more about profits than about anything else is, to say the least, dangerous.

That's why we must keep fighting for net neutrality.