Not sure where to post this question so I am posting it here. I'm sure the admins can move it if necessary.
We are using Zimbra v. 8.0.3_GA_5664. This is the issue we are having. If we are connected to our internal network anyone using a cell phone can send email through their email apps. Alternatively, if you connect through the mobile provider and turn off wi-fi users with T-Mobile, or AT&T can send email through their email apps as well. However, if the user connects to another wi-fi network such as their home network or a local coffee shop wi-fi they get an error indicating that the send failed and the outbound settings couldn't be authenticated as the outbound server couldn't be reached.
I've looked around in the Zimbra settings and have seen no area where these settings could be modified.
Any assistance or suggestions would be greatly appreciated.