Q: We could not complete your iTunes Store request.  The network connection could not be established.

me too - on my pc and iphone3GS but ok on my iphone4

Me too.  Also I purchased 5 episodes of a TV show last night Aprik 15th and only one episode downloaded.  When I tred to download other episodes April 16th  I get the same message as everyone else!

The Parental toggle worked for me, thanks!

Okay, this might help us all...I just did a repair of the main PC iTunes app, then went into the apple devices I use and turned off the match feature, restarted everything and it's working like a charm!!  Across all devices, iTunes and app store is working the way it should.  

the parental toggle did not worked for me. i'm on the Australia iTunes store and it keeps saying "not available in my country"

http://support.apple.com/kb/TS3288 This works for me

yep same here on an iMac running Snow Leopard and latest iTunes...

parental toggle did nothing to help

seems to have started immediately after the Java and Safari updates for 10.6.8 this morning...

Someone broke something for sure.

I've been having the same problem for the past 5 hours (error -50 and I can't sign in). Nothing I've tried seems to solve the problem...

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I didn't do anything since my last post on the 1st page, except wait a few hours and log out and back into Windows and it seems to be working fine now.  I'm guessing there was an issue with the iTunes servers?

now i can login...seems ok to login to itunes store and itunes match. didn't do anything just tried to login

I found this problem on my PC this moring in Thailand.
In my iphone and ipad all OK.

And now I fixed it by toggle parent control 2 or 3 times.

This worked for me also. 

Wish this was out here last night....I had the same problem around 2100 eastern. I searched and didn't find anything out there...I actually uninstalled iTunes and reinstalled on my pc. Our pc has multiple accounts on it, so I tried everything I could think of...After the reinstall, my account was still doing same thing with that -50 error. I logged into my wifes on the machine and fired up iTunes and got some other weird error...Still couldn't sign into itunes under her account either... I gave up... I guess I'll try it again tonight when i get home.. I just hope iTunes didn't mess up anything on the other user accounts on the machine...stupid itunes...