I have problem with mail client in Mountain Lion

I use the iPhone 4 and iPad2 on both devices I Exgange server communication with the server is no problem, but in Mountain Lion I am unable to set the mail client, so to function properly.

I really tried all the advice but nothing worked.😢

I do not get it. Why it on both devices works great, but the MacBook Pro it does not work at all.

Does anybody have similar experience and know someone solution?

Thanks for your help