2019 Fix - Just want to post my solution to 'Origin login is currently unavailable' here, as it still happening in 2019.
After a fresh win10 install, I had internet access to YT, bing, could even download windows updates etc, but yet no connection to Origin or to my router via the usual 198 162 x .1.
Open 'Control Panel\Network and Internet\Network Connections' and you will see several ethernet adapters.
* Unplug your cable and plug into another adapter in your mobo. *
Instantly Origin came online.
I tried all the Reset solutions given from other, none worked.
Just weird...