email sending can be fussy. your away internet provider may restrict who you can use to send outgoing email, or your home internet provider may be configured to only send when you are at home . you have a difference in how the outgoing mailserver is configured on your two devices. the one that works is probably using authenticated relaying. the one that only works at home is probably using unauthenticated relaying to your isp's internal-only outgoing mailserver.
if you copy settings from the working device to the non, check the FROM address being added to the messages, you may need to keep just that entry the same on the problem device.
