There seems to be a bug in the Google AdSense console that is preventing Google publishers from submitting tax information to Google. There are several reports in the Google AdSense Help forums with complaints about this issue.
The issue is, when one clicks on the "Submit your tax information now" button, nothing happens.
This was first reported on Wednesday and Google confirmed the issue saying:
Thanks for bringing this to our notice. I've consulted our specialists on this issue. I'll follow up once they respond.
It is still an issue this morning.