I am having the same issue. Some URLs will not open either on my ipad or iphone, but work fine on desktop.
I forward several newsletters to evernote to read and organize them in one place, and this seems to be a problem with some (not all) HTML emails in evernote in iOS. In some cases, links work fine. In other cases, I can edit the link and at least copy and paste into a browser. In other notes, I cannot even do anything with the link, I just get an error message when I click it.