Can't fix APN MMSC with verizon sim card, outbound MMS texting not working

[WiSeIVIaN]

I am unable to send MMS messages on an unlocked samsung galaxy phone since when the verizon sim card is in, the APN is uneditable but has a blank MMSC.

Per everything online, MMSC should be

• MMSC: http://mms.vtext.com/servlets/mms

How do I fix this?