If you received an error message stating that you previously blocked location access when attempting to use Mobile Sign-in, it is because the browser app you are using is reporting that it is not allowing location access for this site. This could happen if you previously denied the browser access to use your location or it could be an error within the browser app. Either way, you will need to reset the location preferences for the browser app that you are using so that you will be prompted to allow access again. Since this functionality is built into the browser, the process to reset the prompt will be different, depending on the manufacturer and model of the phone as well as the browser being used. We have included articles below that detail how to do this for iOS (iPhone) and Android (Samsung, Google, HTC, or anything other than iPhone) devices.
iOS: Settings > General > Reset and tap Reset Location & Privacy (https://support.apple.com/en-us/HT203033)
Once your location preferences have been reset for the browser you are using, close out the browser app, return to the email or text message where your Mobile Sign-in link is located and try again. Just be sure to look out for a pop up requesting permission to use your location and allow it.