Electroneum, which offers a digital currency that can be mined using smartphones, was due to launch its website and mobile app last Thursday, having crowdfunded millions of dollars in bitcoin and ether following a so-called "initial coin offering", or ICO.
The Maidstone-based company's website came under a distributed denial of service (DDoS) cyber attack last week, forcing it to delay the full launch of its mobile mining app.
DDoS attacks involve a network of compromised computers, known as a "botnet", which flood a website's servers leaving legitimate traffic unable to get through and making the website vulnerable to hacking.
Electroneum, which claims 140,000 people hold its tokens, has locked down the accounts while it tries to bring its network online safely.
Electroneum
Electroneum's website after the attack CREDIT: ELECTRONEUM
The startup created the Electroneum cryptocurrency, with many users buying the token in the hope it will spike in value following the rise of bitcoin, which is now worth more than $7,000 per coin.
Electroneum made headlines last month after it received the backing of football manager Harry Redknapp ahead of the launch, who claimed he was "proper excited" about the crypto-startup.
Electroneum says its platform will allow "the average guy" to mine cryptocurrency using technology similar to the computer programs that allows tokens like bitcoin or ether to be generated, but which normally takes significant processing power.
One user locked out of their account complained on Facebook: "The question has to be asked... why didn't they do all this testing before the launch?"
Another said: "With $40m in the bank you should be able to hire and sort this quicker. This should all have been done before applying/listing on the exchange."
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electroneum 
When one small step...becomes one giant leap #Electroneum #Cryptocurrency #Launching #Blockchain
9:56 PM - Oct 31, 2017
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A statement on Electroneum's website said: "We are very sorry for the continued delay, and understand your frustration. We are working as hard as is humanly possible to complete the works and get everyone live so we can get on with the next (exciting) stage of the evolution of Electroneum."
The Financial Conduct Authority has previously said that there is no investor protection for most ICOs, which operate like unregulated crowdfunding sales, warning people should "be prepared to lose [their] entire stake".
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electroneum
Sunday 18.41 Coding as fast as we can. Working to get this live all weekend. Thanks for patience, Hope for good news this evening!
12:23 AM - Nov 6, 2017
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New cryptocurrencies have been regular targets for cyber criminals. A similar launch this summer saw one ICO lose $7m of digital currency to hackers within minutes of launching.
Interest in ICOs has peaked as the price of bitcoin spiked to more than $7,000 last week as investors and speculators hunt for the next big cryptocurrency, raising fears of a bubble.
Although many ICOs have lost significant chunks of their value as users cash-in their tokens, the crowdfunding method has generated millions in startup funds, even before they launch a product.
Richard Ells, Electroneum's chief executive, has not responded to requests for comment.
