error 504 on itunes when trying to restore/update iphone

[naruk]

so, I tried to restore my iphone to factory settings using my iphone 5 itself. The phone was restoring just fine (with the apple logo and loading bar on the bottom) when it just stuck with the logo.
and when I connected it to itunes, there was a pop-up saying to choose between update or restore. because my phone was running on ios 8.3(jailbroken) it demanded to update to 8.4
and now i'm stuck with an error 504 appearing on itunes every time i connect my phone and choose to update
please help!

My itunes has been updated to the latest version and my laptop has been too. I really can't understand what's wrong and it's driving me crazy.
thank you very much for replying to my problem

 

[Cory Cooper]

-Can you use the iTunes Store successfully when the iPhone is not connected?

If so, you could try putting the iPhone into recovery mode:
If you can't update or restore your iPhone, iPad, or iPod touch

***NOTE: You will lose all data on your iPhone. But, since you are already in the Apple logo loop, you cannot recover data from the iPhone anyway.

C