Can't send e-amil on iMac, iPhone or iCloud but can receive mail.

Good Morning,

I'm not sure this is the correct community for this question.

I cannot send mail via my iPhone, iMac, or iCloud account. I can send via my iPad and can receave e-mail via all these devices. When i send e-amil via my desktop iMac, I get a variation of this popup; "Connections to the server “smtp.me.com” on the default ports timed out.

Select a different outgoing mail server from the list below or click Try Later to leave the message in your Outbox until it can be sent."

I've go into the mail accound and attempted to reset servers to no avail. I find it strang that I can't even send mail via my iCloud account but can via iPad.

Thanks in advance,

mpl