We have users that can’t log in through Instagram or TikTok embedded browser.
- 403: disallowed_useragent for web login from embedded browsers (Instagram / TikTok embedded browser)
Google OAuth does not work in embedded web views per policy. See Modernizing OAuth interactions in Native Apps for Better Usability and Security — Google for Developers Blog - News about Web, Mobile, AI and Cloud
The workaround is to use one of the alternatives recommended in the link, like Chrome Custom Tabs. The possible explanation for why it works in some cases could be related to each user’s mobile configuration, whether they have Chrome as their default browser app.