Try the following it relates to both sending and recieving, posted by the whatsapp team.
Make sure to have a strong internet signal on your phone
Make sure your phone has an internet connection. You can check this by opening a browser and going to a website. If you're having connection problems, try these connection steps
If web pages work, but WhatsApp doesn't, you will need to contact your mobile provider and system administrator and make sure that your APN and router are configured correctly to allow non-web and socket connections.
You may just need to change the notification settings in WhatsApp
- Open WhatsApp.
- Push the Menu Button.
- Tap Settings > Notifications.
In this menu, you have options for Message Notifications and Group Notifications. Adjust the settings to your liking.
If messages are still taking too long to reach your phone
It may be that you are not receiving your message pushes from Google's push notification service.
We recommend that you:
- Reboot the phone (Turn it OFF then ON).
- Try to install Push Notifications Fixer and see if it helps.
- Delete and reinstall WhatsApp.
- Make sure that Background data is allowed under Settings > Data Usage > Menu Button.
- Launch the Hangouts app, press the Menu Button, and sign out of all of your accounts (tap the account, scroll down and select Sign out). Then re-launch Hangouts and sign back in to your account(s).
- Turn off Wi-Fi.
- If you are often connected to Wi-Fi, check your Wi-Fi sleep policy (Settings > Wi-Fi >Menu Button > Advanced > Keep Wi-Fi on during sleep) and make sure it is set toAlways.
- For Android OS 4.4 and above, make sure that Wi-Fi optimization is unchecked (Settings > Wi-Fi > Menu Button > Advanced > Wi-Fi optimization).
- For HTC devices, try turning off fast boot in Device Settings > Power > Fast Boot(make sure it is unchecked). You may also try turning off Power Saver, Extreme Power Saving Mode and Sleep Mode. Make sure to reboot your device after changing the settings to ensure the changes are applied.