I recieved email but the problem cannot SENT email

Start here:

Get help with Mail on iPhone, iPad, and iPod touch - Apple Support

You may try restarting your device first:

• Press and hold the Sleep/Wake button
• Press and hold on the Home button
• Keep holding both buttons until the display turns off and back on with Apple logo on it.

If it does not help:

Delete the account in Mail application and then set up the account again. Navigate to Settings/Mail, Contacts, Calendars / Accounts Tap on the Account, then on Remove Account button

Add an email account on your iPhone, iPad, or iPod touch - Apple