By the way, it may not matter, but you have posted your message in the section of this community given over to Home WiFi Adapters and Powerline. (This is easily done, given Netgear's impenetrable community structure.)
If you need more help, you might get better and quicker replies, and find other answers, over in the appropriate section for your device:
No need to repost there, unless you want to – that will just clutter up the place with duplicated messages – but you might find advice related to your hardware.
I have asked the Netgear moderator to move your message.
@Blueface wrote: I need help because I got a new router but when I got to fix the WiFi extender it asks me for a username and password but I never created one
Some famous (?) software minds had the famous idea to abandon the default admin/password username and credentials, replacing it by a username consisting of an email address and a password at the initial installation (or probably some later firmware upgrades) - without allowing to do some password recovery using that very same email - on these basic wireless extenders.
As you have a new router, the most easy way is to re-configure the EX2700 from scratch - use the Factory Reset Button (-> NETGEAR N300 WiF Range Extender Model EX2700 User Manual, p.34 ff "Return the Extender to Its Factory Default Settings". Then re-configure following the N300 WiFi Range Extender Model EX2700 Quick Start Guide. Don't forget to take notes of the username (email) and password configured, probably also from the recovery questions and answers.
