So I send out login links in emails. If the user clicks on the link, JavaScript in that webpage will *POST* to a URL to log in. The login token works only *once*. I now have a user that tells me they can't log in. From the logs, I see a Microsoft IP address POSTing that login link. Is some kind of MS email security product executing JavaScript and POSTING things? Is this a known phenomenon? I've now made this a login *button* which the user has to click again. I hope it helps.