Managing your subscription
When you click 'Manage Subscription' to log in to a status page, we use a magic link authentication method. This sends an email to the subscriber email address, which includes a unique, one-use link which authenticates the subscriber to the status page.
Once authenticated via the magic link, the session is stored in the browser that keeps you logged in for some time.
403 Link already used
Sometimes, if a magic link is visited more than once, a 403 error is presented as the link has already been used. A new magic link must be regenerated by returning to 'Manage Subscription' and requesting a new login link.
Email addresses using Microsoft 365 / Office 365
For email addresses provisioned with Microsoft 365 (Office 365) and on a relevant plan that includes Microsoft Defender, magic links will present a 403 error even though the subscriber hasn't clicked on the link.
Microsoft Defender has a feature called 'Safe Links' that pre-scans URLs. In the background, Safe Link technology crawls the URL, which means this has a one-time visit to the link.
As a workaround, a Microsoft admin on the organisation's domain needs to create or update a new Safe Link Policy to exclude the status page URL from being crawled.
If you would like more details, you can visit the Microsoft Help article.
Subscribers using a free/premium outlook.com address may experience a similar issue.