Can't send email

I’m using Mac OS X.5.6 and Mac mail app 3.5 and all was working fine until tonight. Suddenly, without changing any settings, mail will not send. Please advise asap. Thanks.

Mine works. I’m using SSL and have my outgoing set to Are you using SSL? Can you receive? What mail server setting? Like mine, or


I’m using and somehow the outgoing server port changed and was not able to send messages. Have no idea how that happened but I changed it to another and it’s working fine now. Very weird. thanks foryour reply.