There are so many ways to resolve the Linksys RE6700 extender issues. Consider all the tips one by one. 

First, visit the Linksys RE6700 setup management page, by entering the default web address in the search bar. Now, find an administration option and then hit on the software upgrade. Next, if you see any latest versions of the software file then install it on your computer. Make sure your laptop or computer must be connected to the Linksys RE6700 WiFi range extender network. In the end, you will need to restart your extender to finish this upgrade process. 

We recommend you fix the extender issue and turn off your extender device. After turning it off, take out the Linksys extender power plug from the power socket. Now, wait for a short while and put back the extender plug into the power socket, and turn it on. 

On the left side of the Linksys RE6700 extender device, you see the reset button. Now, push that button for 10 seconds with the help of a hairpin. After pressing the reset button, all the LEDs of the extender will turn off. As it means the extender device is completely reset now. 

Note: After the reset, do again the Linksys RE6700 setup process.