Gmail for Android Is Not Sending

Internet Access

Before you do anything, you should make sure you have Internet access. If you don't, then of course that's the reason you can't send any emails. Look in the top right portion of the display to see the network coverage indicators. You will know that you have data access over your cellular network if you see a green 'E,' '3G' or '4G' icon, and a green icon shaped somewhat like a triangle means you have Wi-Fi access. If those icons are white, your connection isn't active, and you may need to move around a little to get a stronger signal.

Basic Troubleshooting

Sometimes the solution is as easy as opening the message and tapping the 'Send' button again; occasionally messages get stuck sending if you don't have Internet access when your device tries to send the message for the first time. Another option is to press the 'Menu' button and tap 'Refresh' to force the device to sync itself with Gmail's servers. If none of those help, you should try turning your device entirely off and then back on, and attempting to resend the email.

Auto-Sync

Emails won't send if the Android device's auto-sync option is disabled. Disabling this feature can help you reduce data usage, but in many cases emails won't send without you taking extra action each time you want to send something. You can check this feature by going to the Home screen and pressing the 'Menu' button and tapping 'Settings,' then 'Accounts & sync.' You can enable or disable 'Auto-sync' at this screen, and you can enable or disable 'Background data.' Background data controls auto-sync, so if it's off, auto-sync is off as well. If the former is off, the latter is off as well. You can enable both of them, even just temporarily, to try to get your messages in Gmail to send.

Clear Cache

In rare cases, data stored in the Gmail app's cache can cause obscure errors that many Android users have reported result in problems sending emails. If you clear Gmail's cache, you shouldn't lose any important data, but it may fix an error causing problems with sending a message. Go to the Home screen and press the 'Menu' button; then tap 'Manage Apps,' then the 'All' tab. Locate the Gmail app in the alphabetized list and tap it; then tap 'Clear cache.'