The Instagram web version is unavailable due to expired SSL certificate
On the afternoon of April 30, the SSL security certificate expired at the Instagram.com website, which made the web version of one of the most popular photo apps out of the reach of all browsers. At least that's the way The Next Web explains what happened.
At the end of January 2015, Instagram and Facebook already had serious problems that caused both sites not to open to a significant proportion of users in different countries. Then the problem was eliminated in 40 minutes.
UPD: Apparently, the certificate error was corrected - from Russia the web version of Instagram opens.