Hello micchamp,

As your unable to login on Phone app and change your router name and password , could you let us know the model number of the modem and are you trying to download the Surfboard Central App ?

If its Surfboard Central  App do you see any error code?

We also have another option as : If you could let us know the model number of the modem it will be easy to access the web manager page and change the router name and password 

Error Code:  0000-1612

SBG8300

I have reset the dive.  No change.

Hello michamp, 

We understand that after doing the reset still unable to login on Surfboard Central App. 

Lets try the following steps again:

Uninstall the Surfboard Central App

http://arris.force.com/consumers/articles/General_FAQs/SBG8300-Factory-Reset

Reinstall the Surfboard Central App 

If still not able to connect to Surfboard Central App

We have an other option to login on webmanager page: follow the below link for the same:

http://arris.force.com/consumers/articles/General_FAQs/SBG8300-Changing-the-Wi-Fi-Name-and-Password