Check to ensure your mobile device is connected to a mobile network or Wi-Fi.
Check that the account information provided in the set-up process is valid.
Check your account settings to see if you have exceeded any of the mail limits.

Verify Connectivity:

Check to ensure your mobile device is connected to a mobile network or Wi-Fi.

Check Account Information:

Check that the account information provided in the set-up process is valid.

Check Mail Limits:

Check your account settings to see if you have exceeded any of the mail limits.