El Salvador became the first country to adopt bitcoin as legal tender on Tuesday, but the roll-out stumbled in its first hours and President Nayib Bukele said the digital wallet used for transactions was not functioning. For part of the morning, El Salvador’s president became tech support for a nation stepping into the world of cryptocurrency. Bukele marshaled his Twitter account – with more than 2.8 million followers – to walk users through what was happening. Bukele explained that the digital wallet Chivo had been disconnected while server capacity was increased. The president said it was a relatively simple problem....