Problem in sending emails: Failed To Connect To Server

Hi techyv masters, I am posting here my problem in sending my emails, my email failed to be sent because of an error message that I can't connect to the mail server.
Alert
Failed to connect to server mailqs2056.pair.com
As I am pondering on the error message, It is pointing the error to my connection towards the mail server, because of that I check on my internet connection, it seems to be up and running because I can browse the internet, and there is no settings on my computer that will restrict me in sending emails, I already check on what is necessary based on my knowledge,
Please share some thoughts on what else shall I check,
Thanks.
