Starbucks wireless login

I have Safari 9.3.1 on Macbook AIR 2013 with El Capitain 10.11.6 installed. Since the security update September 1st 2016 and/or the Safari update at the same time, I'm unable to log in to Starbucks wireless where there is a pop up authorization window with Safari. I am able to receive the pop up window in Chrome, but prefer to use Safari.

I have followed guidelines provided re: allowing pop up windows, then disabling pop up windows and back again, same thing with extensions in the library folder, but nothing works to fix the issue. I don't want to switch to Chrome, but unless there's a way to allow wireless log in with Safari, I'm done. I doubt I'm the only one having this issue? Any suggestions (other than what I've posted I tried already) are welcome.