My apple mail was fine till a week ago when I had to restore everything. I am trying to configure my apple mail to work through gmx mail. I'm receiving emails fine however cannot send. I get this error: "This message could not be delivered and will remain in your Outbox until it can be delivered. The sender address firstname.lastname@example.org was rejected by the server" Just need to know how to fix this as it's quite important for my business, any help will be well appreciated.