Usually, your Macard extender flashing blue light indicates that either your device is running into a connection problem, your device is either in the process of pairing or maybe its hunting for a signal. If you depend on the extender for constant internet all over your area, then knowing what causes this flashing and how to fix it is really vital. https://gomacard.online/how-to-connect-macard-wifi-extender-to-tp-link-router/