Who I have the same questioned this topic

ICYMI:

NOTE: today, while on the phone with a Level 2 tech, I had to Google to find the password for my 4G LTE Network Extender 2.

I hope this might help others who are trying to get their Extenders up and working...

4G LTE Network Extender

Default Password  The default administrator password is LteFemt0. (Case sensitive. Note that the last character is a numeral zero.)

User Guide https://www.verizonwireless.com/dam/support/pdf/4G_network_extender_user_manual.pdf

4G LTE Network Extender 2

(Currently shipping)

Default Password  The default administrator password is LTEFemto + last 4 digits of the MAC ID (e.g., LTEFemto00A3). The MAC ID can be found on the label on the bottom of the Network Extender.

User Guide  https://www.verizonwireless.com/dam/support/pdf/user_guide/samsung-network-extender-2-user-guide.pdf

Remember, if your Extender is in a DMZ in front of your firewall, pick a complex, 20-character long password, to protect it from attack.