Logging out of FB, clearing my web cache, and logging back in doesn't fix the location issue. After ending all activity on the FB Security and Login settings, which forced my calendar app and all the others (like Bumble) to disconnect, then logging back in, my location corrected. This question is a great opportunity to point out that FB badly botched the handling of this. Being unexpectedly logged out and asked to login again looks just like phishing and it should be treated as such by users. As far as I'm aware, Facebook don't actually block the new attempts from different IPs. Instead, they send an email to the registered email address with a notification that you logged into a new device, with a button to mark this as legitimate or malicious. The tracking appears to work not only via your IP, but also a long-term identification cookie and other browser fingerprint data (e.g. My FB account received several activity events from android apps, even though FB app is not installed on my phone. I have logged in using phone's chrome browser, which is now logged out and cookies cleared. For example, lets say for Facebook login the steps are: The user will click on FB Login button. The user will be asked to login to Facebook and allow permission. If user allows it will return an authorization code. Now we will use the authorization code to get an access token. We can store the access token in session to start a user session. Only you and FB know that secret. So FB can fail the verification if app secret and the app id in the token don't belong to the same app (there's actually another step involved before verification - you must first get an app access token, in order to use it with the verification endpoint, and in order to get the app token, you must provide your. Additionally, sometimes my FB login page looks weird and unlike the regular page (browser injection?) Then, there are these chinese alphabets in the attached image: A lot of services, sites, and applications offer the 'login with Facebook' or 'login with Google' option. For many sites, the browser opens a separate window in which you can enter your username and password. This way, you can check the URL and convince yourself that the origin really is Google/Facebook/whatever. My opinion is that, every now or then FB makes roll outs , try new features, They might had tried some kind of localization on the sms/login-token features. If only one of your phone numbers have only this problem, you may also have to consider the possibility of a fault from service provider. When I use Facebook, after I log out, I can see my profile picture on the login screen of Facebook. With great curiosity, I click on the profile picture (while I am still logged out) and Facebook l.