Connect to the modem over WiFi or with an ethernet cable
Open a web browser
Clear the URL bar and then type 192.168.0.1 and hit Enter - If you do not see the login page for the modem, then try 192.168.1.1 and hit Enter
You should see a box asking for the modem password
Password is either attadmin or ADMIN#1
Click Settings
Click Network
Click Connections > Click on Turn off mobile data
Click Apply
Click APN
Click Add
In Profile Name box, type - VZ
In APN box, type - so01.VZWSTATIC
PDP Type: IPV4
Authentication: none
Click Save
Click Profile Selection and then click VZ
Click Set Default
Click Connections> Click on 'Turn on mobile data'
Click Apply
Power the modem off
Wait 30 seconds
Power the modem on again
Wait 60 seconds and then see if it works.