Online trading platform eToro is back online after a technical problem led to a global outage amid a sell-off of cryptocurrencies. The Israel-based service, which has surged in popularity during the pandemic, had been inaccessible to users since Tuesday. The service was back online on Wednesday morning. Tuval Chomut, eToro's chief solutions officer, said the trading platform outage was not caused by "a breach or an attack on our systems". "The reason for the service disruption was a technical issue that affected our Microsoft database and we were forced to move the platform into maintenance mode," he said. "We worked hand in hand with senior engineers at Microsoft to identify and resolve the issue, but this took longer than any of us would have wanted." The company said it would be introducing temporary changes to respond to the demand. "We will be raising the minimum first time deposit amount to $1,000 effective immediately and increasing the minimum copy value to $500. We will also be temporarily removing the option to request future market entry orders," Mr Chomut said. "These are unprecedented times both in terms of the market conditions and eToro's growth. We have more and more new users coming to the platform each day, a huge increase in trading volumes and strong growth in our users' engagement with the feed and other aspects of our social investment community. "This means that when things go wrong more people are affected and we take this responsibility very seriously. We want to assure you that providing a frictionless trading and investing experience is our highest priority." eToro, which allows users to trade shares with their mobile phones, grew its user base by about a third in 2020. The crash comes as Bitcoin traders lead a sell-off in the cryptocurrencies market. The market dropped 14 per cent in the past 24 hours, according to CoinMarketCap.com. The slump was led by Bitcoin, which accounts for 60 per cent of the cryptocurrency market by value. The sell-off coincided with comments from US Treasury Secretary Janet Yellen. She said Bitcoin was "extremely inefficient" as a means of payment and highly speculative.