icloud: Send Mails very slow

Good afternoon,

when i send mails through my iCloud account in the OS X Lion Mail Program, the sending speed is going down to about 50 KB/S (suggested at the activity section in Mail)

But effectively sending a Mail with a picture attached (jpg size = 60 KB) doesn't work. Within two minutes, the progress bar is at 50% then no futher progress is recognizable. Activity log shows still about 60 KB/s.

Configured is mail like this:

at the Tab "Advanced" Port 993 and SSL is turned on.

Server for incoming mails is grayed out.

Do i have configured something wrong?

I have also checked my router settings.

My mother also have an iCloud mail adress, and the same problem exists.

Her computer is not in the same house. So i don't believe, that my router / environment cause the problem.