E-mail stuck in Outbox's Mail app

Hello everyone,

I have been searching for a post regarding my question but I wasn't able to find one. Maybe you can help me.

I tried to send an e-mail with an attachment using the Mail app in my iPhone 6 running on iOS 9.2.1 but the e-mail got stuck in the Outbox because, I believe, the attachment is too heavy.

Now I am trying to delete the e-mail in the Outbox by sliding it to the left and pushing the red bin button but, as it is always trying to send it (the little circle is always active), I can't do it this way. I already restarted the iPhone but it didn't change anything.

Does anyone have a suggestion?

Thank you in advance.

Best regards,

Afonso Piçarra