I do not have a 401, but I'd say you definitely found the problem. Looks like your phone was shipped with incomplete programming.
The 'gateway' (of 121) is the SMS to mail gateway number. Like a port number on a router.
Yes it should already be in your phone. Along with an address directing which message center to send it to. I have seen that address vary a little.
With you sending a picture, that would be an MMS to mail....
If you know how to -safely- go into code entry mode, what does your parameter 122 say? If that too is blank, oh boy.....
My LG420G and LG600G, uses a gateway of 121, and it does show up in my phone settings.
I hate to drop off anyone at Net10's CS door, but really, in this case, I thinking calling customer service using their Miami number, is the only way on that one.
If you do this, could you please tell them that suddenly, we're seeing a lot of their phones not programmed correctly, here on HoFo. If they don't believe you, they only have to look at the top few threads of the TracfoneNet10 thread. I mean this sincerely.
Please let us know how things turn out for you.
Good luck ~ K-L-M