iPhone 6 won't connect to computer

I have an iphone 6 which is on the ‘restore to itunes‘ screen. Plugging it in to the normal outlet charges the phone totally fine. However, if I try to connect it to my windows laptop, it charges for a small second and then it stops charging. It also does not show up in itunes. I used the same (original apple) cable and other USB devices seem to work fine (suggesting there is nothing wrong with the USB on my laptop). Does someone know the issue or is there someone who can explain this or help me fix it.

I have cleaned the charging port and disconnected / reconnected the dock connector on the motherboard but it does not seem to fix the issue.

Help would be very much appreciated! Thanks.

Edit: Earlier it showed a message saying something like ‘authorize accessory’, but for that I had to log in, but I didn’t have the passcode.