Problems with iTunes Match

Hey Guys,

I'm experiancing really annoying issues with iTunes (11.1.2) on my Mac, continously asking me to sign in, in order to enable automatic downloads.

It keeps on asking me but doesn't seem to see that I'm already signed in, and when I resign, it asks me again.

Plus, it prevent iTunes Match from working and I can't play my music. Plus, I have problem with Match on my iPhone, certain albums refuse to sync.

Also, this happens, after a clean install of both my Mac & iPhone, and having succesfully configured Mac and iTunes Match, the first time I plug my phone to sync.

I've tried everything:

-Sign off and re-sign in, from Mac & iPhone,

-disable iTunes Match, automatic downloads... o iPhone,

-sign off iCloud on both Mac & iPhone,

-totally reinstall iTunes (also the preference files of iTunes),

-reinstall my Mac & iPhone os,

-try to make my head enter the cd player of my Mac while inserting my iPhone in one of my ears.

Seriously, I'm becoming mad with these problems.

Someone got an idea? Please?