Alexa.com claiming of websites has been retired on may 2016.
So to claim your website with HTML, GOOGLE ANALYTIC and HTML UPLOAD is no longer active. I.e no more claiming of websites on Alexa.
See Alexa retired claiming message i got when trying to claim a site for a friend, "The Claim Your Site feature was retired in late May 2016. Is your site's contact information out of date on Alexa? Simply contact us and we'll be happy to help.
Note that we do still offer our Certified Site Metrics feature, which you can use to get your site's traffic directly measured. You can even use the directly measured traffic to get a more accurate ranking for your site."
So now site metrics is the way to measure your site traffics which you will activate with their subscription bill.
For now i cant say if this new development on Alexa will affect already claimed sites, but i will try my best to keep writing more about it, and the possible way out if available.