Cannot send or reply to emails. Any suggestions?

Installed about two weeks ago to replace Outook Express.  Cannot send a new email or reply to one that has been sent to me.  Suggestions?

Hi Nancy,

Who is your e-mail provider (e.g. Google or Microsoft)?

Which SMTP settings are you using?

Email provider is Earthlink.  Where do I look for the SMTP settings?  We receive emails but when we try and send something or reply to something it just sits in the outbox.

Tools > Accounts > “select relevant e-mail account” > tab page ‘SMTP’

screen shot:

Hi Nancy, how did you setup the account? Did you import the account from Outlook Express or did you setup the account using the automatic setup?
Can you please make a screenshot of the SMTP settings as Hans suggested?

Thank you,

I had someone do it for me.  I need to contact them to see how they did it.  Hopefully in the next day or so I will have the answers.