Mobile devices using web preview will encounter an issue when generating recovery links via text message. The web preview feature of mobile devices go and 'pre-fetch' the website to provide a snapshot of the site in the text message. This pre-fetching actually uses the link in AMS and then when the user visits AMS, it reports the link has already been used.
The fix is to disable web preview on the mobile device: https://www.sammobile.com/2017/04/26/psa-galaxy-s8s-messages-app-shows-web-link-previews/
In efforts to programmatically detect these devices, we have added some validation to detect and block these ‘pre-fetch’ algorithms from spoiling the recovery link. The following error message may be displayed when using a recovery link: This browser is not supported. Please try another browser (such as Safari, Chrome, or Firefox) or update your current browser to its latest version.
All major browsers are supported and most likely any user seeing the above message has an significantly outdated version of the Firefox browser they are using (only blocking <= v. 24). If by chance they are using a legitimate browser or Firefox v. 24 or less and still seeing this message, they will need to update the current browser or use an alternative up-to-date browser.
The following user agents are being automatically blocked from recovery links as they have been proven to be web preview agents:
- “Apache-HttpClient” (older Android versions)
- “Mozilla/5.0 (X11; Ubuntu; Linux i686; rv:24.0), Gecko/20100101, Firefox/24.0” (newer Android versions)