"iPhone is disabled, connect to iTunes" Cant back up anymore?

Hi,

I have forgotten my passcode, after trying for a few times, my iPhone showed "iPhone is disabled, connect to iTunes",

In this stage, i couldn't back up my phone anymore?

When i connected to iTunes, it showed "To allow access, please respond on your iPhone", but nothing popping out on my iPhone.
I have to back up my phone before restoring it.

Many thanks,
Tang