[1] The Linksys E4200 router comes in two hardware versions, v1 and v2.
Version 1 does not require a username, while Version 2 requiresadminas the username.
it’s possible for you to find your unit’s manual inPDFformat fromLinksys Support.

Linksys
This easy-to-guess and easy-to-find password shouldnotstick around throughout the life of your router.
Change your router’s default password once you’re logged in to make your internet more secure.