Phone works, texts work (SMS and MMS), but internet error is "unable to find hostname". I think the phone still recognizes the ATT WAP settings (att internet) as default (there does not appear to be a way to delete the default WAP setting). I don't know how to change ST NET to be the default. I've combed the user manual and searched every phone menu.

THanks in advance for any help.

My settings:
What was on the att z431phone (Access point):
Name: wap(dot)cingular
APN: wap(dot)cingular
Authentication: none
Username:
Password:

What I changed att z431 to (access point):
Name: att(dot)mvno
APN: att(dot)mvno
Authentication: none
Username:
Password:

What was on the att z431phone (internet Profile for MMS):
Name: AT&T MMS
Home page:
APN: wap(dot)cingular
Proxy: on
Proxy address: wireless(dot)cingular(dot)com
proxy port: 80
MMS center address: h t t p (colon slash slasht) mmsc(dot)cingular(dot)com

What I changed the att z431phone to (internet Profile for MMS):
Name: ST MMS
Home page:
APN: att(dot)mvno
Proxy: on
Proxy 66.209.11.33
proxy port: 80
MMS center address: h t t p (colon slash slasht) mmsc(dot)cingular(dot)com

What was on the att z431phone (internet Profile for internet):
Name: ATT WAP
Home page: h t t p (colon slash slasht) home(dot)att(dot)com
APN: wap(dot)cingular
Proxy: on
Proxy address: wireless(dot)cingular(dot)com
proxy port: 80
MMS center address:

What I changed the att z431phone to (internet Profile for internet):
Name: ST NET
Home page: h t t p (colon slash slasht) home(dot)att(dot)com
APN: att(dot)mvno
Proxy: on
Proxy address: proxy(dot)mvno(dot)tracfone(dot)com
proxy port: 80
MMS center address: