1. Check if your Wi-Fi connection is strong and working properly.
2. Go to Settings on your Phone and turn Airplane Mode on then off.
3. Make sure your device is connected to the correct network as your inbox.
4. Ensure your Device’s time and date are updated
5. Check the Port Settings and whitelist your domain.
6. Ensure your email account is not full, and won't accept emails.
7. Make sure you have enough space on your device to receive emails.
8. Check other email programs and apps installed on your device. Make sure they are not redirected to a different account or disabled.
9. Clear your cache, data, and fields in your email and other apps.
10. Re-start your device and follow instructions as per manufacturer’s recommendations.