I use Chatteremail on a Verizon 700P to send Optonline.net email. The SMTP profile needs to be Verizon, not Optonline. Depending on what carrier you use, you may have to adjust your SMTP profile accordingly. I have posted below Verizon's confuguration. Hope that helps. If Verizon is not your carrier, tell me which is, and I will post the settings for it.
Verizon:
To configure Chatter to send email using Verizon's SMTP server, go to your Server Account settings. Enter the POP3 setting as per your ISP's instructions and enter the following for the Outgoing Mail Server:
SMTP Server: smtp.vzwmail.net
Username: [your 10-digit cellphone number followed by @vzwmail.net]
Password: [your password that you set up on the vtext.com webpage]
Verizon sometimes assigns you a temporary password in certain circumstances. Some people have reported that they can suddenly, without changing anything, no longer send Email messages using Verizon's SMTP server. A possible cause for this is that the temporary password has expired. You should go to the
www.vtext.com web site to attempt resetting the password. If that fails, then you will need to contact Verizon support directly.
Also note: Sometimes it can take a few hours (as many as six in a few cases, up to 48 hours in rare cases) for the account and password to get set up and become active in Verizon's systems. If your attempts to use their servers don't work right away, wait a few hours and try again.