First, you never know whether that is true or is a deceptive solicitation to install something even worse. Be very cautious about any suggested downloads. I suggest checking the following: (1) Disable or remove any unknown add-ons from your Firefox See: [[Uninstall Firefox for Android add-ons]] (2) If you do not already have a security app for your phone, consider using one or both of the following, or another security app that looks good, which you can install through the Play store app: * Lookout: https://play.google.com/store/apps/details?id=com.lookout (quieter) * CM Security: https://play.google.com/store/apps/details?id=com.cleanmaster.security (more features, but constant notifications can be annoying)