Unable to send or receive emails from certain accounts periodically

Hi there,

I have a MacBook Pro running Mavericks and am using Mail to manage my email. I consistently get an error sign next to one or more of my accounts, even though the details are definitely correct, and also some of my SMTP sending servers are labelled as offline. This happens periodically and then all of a sudden will start working again for 10 minutes then shut down again for the next few hours!

I know this has been brought up a couple of times in other Discussions but none of the tips there have helped me. I have cleared all my keychains and re-added them in, I have changed my password at the client side and I have deleted the accounts and re-added them.

I'm frustrated and really need this to work. Please can someone help me!

Thank you!