Why does my Android phone only download mail on Wi-Fi networks, and not on cellular networks?
We occasionally hear from customers with an Android phone that successfully downloads mail on Wi-Fi networks, but not on cellular networks. The symptom is that when it’s not on a Wi-Fi network, the phone will either act like there’s no mail waiting, or it will download some parts of the mail but not attachments.
This is usually caused by options chosen in the phone settings.
If the phone acts like there’s no mail waiting
If you’re sure there’s mail waiting (for example, because you’ve checked it in webmail), but the phone doesn’t show the mail at all, first try try to manually check or “sync” mail. If that doesn’t help:
Choose Settings > Mobile Data, then make sure “Restrict Background Data” isn’t enabled, either globally or for the mail application.
Choose Settings > Data usage > Mobile and make sure that “Mobile data” is enabled. If a “mobile data limit” is chosen, ensure that you haven't reached that limit.
If the phone won’t download attachments
If the phone shows new mail, but hasn’t downloaded the message attachments, try to manually check or “sync” mail. Some apps don’t download attachments over cellular connections unless you do it manually.
Also, look at the Android settings for the mail app you use. Some apps have an option to save on data usage, and require you to explicitly enable an option to download attachments on cellular connections.
If that doesn’t help, try the general tips in the section above, too.